==== Front PLoS One PLoS One plos PLOS ONE 1932-6203 Public Library of Science San Francisco, CA USA 10.1371/journal.pone.0288041 PONE-D-22-31148 Research Article Medicine and Health Sciences Health Care Nursing Science Medicine and Health Sciences Mental Health and Psychiatry Psychological Stress Biology and Life Sciences Psychology Psychological Stress Social Sciences Psychology Psychological Stress People and Places Population Groupings Ethnicities Asian People Thai People Medicine and Health Sciences Mental Health and Psychiatry Mood Disorders Depression Biology and Life Sciences Neuroscience Cognitive Science Cognitive Psychology Learning Human Learning Biology and Life Sciences Psychology Cognitive Psychology Learning Human Learning Social Sciences Psychology Cognitive Psychology Learning Human Learning Biology and Life Sciences Neuroscience Learning and Memory Learning Human Learning Biology and Life Sciences Psychology Emotions Anxiety Social Sciences Psychology Emotions Anxiety Biology and Life Sciences Psychology Psychometrics Social Sciences Psychology Psychometrics Medicine and Health Sciences Medical Conditions Infectious Diseases Viral Diseases Covid 19 Validation of depression, anxiety, and stress scales (DASS-21) among Thai nursing students in an online learning environment during the COVID-19 outbreak: A multi-center study The Thai version of depression, anxiety, and stress scales Wittayapun Yuwadee Conceptualization Data curation Formal analysis Funding acquisition Investigation Methodology Visualization Writing – original draft Writing – review & editing 1 2 https://orcid.org/0000-0001-9557-2199 Summart Ueamporn Formal analysis Investigation Methodology Writing – original draft Writing – review & editing 3 * https://orcid.org/0000-0003-1503-0336 Polpanadham Panicha Investigation Writing – review & editing 4 https://orcid.org/0000-0002-8237-2558 Direksunthorn Thanyaporn Writing – review & editing 5 Paokanha Raweewan Investigation Writing – original draft Writing – review & editing 6 Judabood Naruk Investigation Writing – original draft 7 https://orcid.org/0000-0002-7207-6739 A’la Muhamad Zulfatul Investigation Writing – review & editing 8 1 Movement Science and Exercise Research Center-Walailak University (MoveSE-WU), Walailak University, Nakhon Si Thammarat, Thailand 2 School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat, Thailand 3 Faculty of Nursing, Roi Et Rajabhat University, Roi Et, Thailand 4 Faculty of Physical Therapy, Huachiew Chalermprakiet University, Bangkok, Thailand 5 School of Medicine, Walailak University, Nakhon Si Thammarat, Thailand 6 Faculty of Nursing, Ratchathani University, Udonthani Campus, Udonthani, Thailand 7 Faculty of Nursing, Chalermkarnchana University, Srisaket Campus, Srisaket, Thailand 8 Faculty of Nursing, University of Jember, Jember, Indonesia Khraisat Omar M Editor Al-Ahliyya Amman University, JORDAN Competing Interests: The authors have declared that no competing interests exist. * E-mail: yogiueamporn@gmail.com 30 6 2023 2023 30 6 2023 18 6 e028804111 11 2022 18 6 2023 © 2023 Wittayapun et al 2023 Wittayapun et al https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The Depression, Anxiety and Stress Scale (DASS-21), an introductory scale used to identify common mental disorders (CMDs) among adults, was validated across cultures in Asian populations; nevertheless, its capacity for screening these disorders may be limited for some specified groups, including nursing students. This study attempted to investigate the psychometric scale’s unique features of DASS-21 for Thai nursing students in an online learning environment during the COVID-19 outbreak. A cross-sectional study using the multistage sampling technique recruited 3,705 nursing students from 18 universities located in south and northeast Thailand. The data were gathered using an online web-based survey, and then all respondents were divided into 2 groups (group 1, n = 2,000, group 2, n = 1,705). After using the statistical methods to reduce items, exploratory factor analysis (EFA) using group 1 was performed to investigate the factor structure of the DASS-21. Finally, group 2 used confirmatory factor analysis to verify the modified structure proposed by the EFA and assess the construct validity of the DASS-21. A total of 3,705 Thai nursing students were enrolled. For the factorial construct validity, a three-factor model was initially suggested containing 18 items (DASS-18) spread across 3 components: anxiety (7 items), depression (7 items) and stress (4 items). The internal consistency reliability was acceptable with Cronbach’s alpha in the range of 0.73–0.92for either the total or its subscales. For convergent validity, average variance extracted (AVE) showed that all the DASS-18 subscales achieved convergence effect with AVE in the range of 0.50–0.67. The psychometric features of the DASS-18 will support Thai psychologists and researchers to screen CMDs more easily among undergraduate nursing students in tertiary institutions who enrolled in an online learning environment during the COVID-19 outbreak. Internal research grants of Walailak University’s Individual Research Grants WU-IRG-65-015 Wittayapun Yuwadee This study was supported by The Walailak University's Individual Research Grants provided funding for the study (Grant Number WU-IRG-65-015). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Data AvailabilityAll relevant data are within the manuscript and its Supporting information files. We have already generated our minimal data set 2,000 datasets out of the total (3,705) (D1.XLSX). OutbreaksCOVID-19 Data Availability All relevant data are within the manuscript and its Supporting information files. We have already generated our minimal data set 2,000 datasets out of the total (3,705) (D1.XLSX). ==== Body pmcIntroduction Depression and anxiety are common mental health disorders (CMDs), leading causes of disability and have gained prominence due to their growing global burden [1]. Individually, these disorders contribute to poor psychological wellbeing, which interferes with learning and inhibits students’ academic performance [2]. Early screening for anxiety and depression in primary care and academic settings necessitates an assessment strategy that is rapid and easy to apply and has proven psychometric properties [2]. During the COVID-19 pandemic, undergraduate students also reported their anxiety or stress [3, 4]. According to a network study, 932 nursing students were included. More than one third of these students reported at least moderate symptoms of worry or stress, and almost one half of these students presented at least mild symptoms of depression [5]. Due to a quick shift from face-to-face to an online learning environment during university lock downs, undergraduate nursing and midwifery curricula had trouble adjusting to "remote learning" that relies on the use of electronic technologies and media sources to conduct learning outside of the traditional classroom [6]. Thus, being unable to participate in extensive training such as clinical settings make students feel as though they are passing up a good opportunity to learn these abilities that may have decreased students’ mental health [5, 7]. In addition, anxiety and depression may occur more commonly among low experienced apprentices including nursing students [8]. Moreover, this current study also discovered that the levels of anxiety and depression were higher among nursing students than among those students from other disciplines, regarding their probably high risk of infection exposure and fear of communicable diseases [8]. Currently, rare evidence is available concerning the mental health of Thai nursing students encountering an instant psychological response in relation to COVID-19. To provide psychiatric interventions to people experiencing these negative emotional states, early diagnosis of these diseases is essential [2]. Early assessment, using an effective screening instrument (such as a rating scale), provides a rapid indicator of the client’s emotional well-being and is helpful for further clinical judgment and early treatment. Likewise, self-reported questionnaires and clinician-rated scales are two commonly used methods to assess CMDs [9]. The Depression, Anxiety, and Stress Scale (DASS) is a common scale frequently used to detect CMDs [10]. Both the DASS-42 and its shortened version, the DASS-21, are frequently used to assess depression, anxiety, and stress among adults, and are considered superior to other psychometric tools to identify these CMDs and screen for psychological abnormalities [11]. Moreover, DASS-21 has several advantages over the original 42-item version (DASS-42), such as fewer items, cleaner factor structure and smaller interfactor correlations [12]. Data analyses among adults using this measure produced consistent results regarding its psychometric properties [2, 7, 12–14]. Findings regarding the DASS-21’s factor structure are contradictory, ranging from one to four factors structures [15–17]. Results from a prior study in Asia, conducted among nursing students in Brunei, have validated the DASS-21 used the final model, including a nine-item scale across three components [18]. However, this study encountered limitations because this representative sample (n = 126) was the smallest compared with other studies. In the Thai context, DASS-21 has been validated across cultures among Asian residents from various projects and research objectives such as assessing the work-related stress and coping strategies among employees in the education and health care sectors [19], so its ability in detecting these mental health problems may be limited for specific groups including undergraduate nursing students. Another study enrolled preclinical medical students to explore psychometric properties of DASS-21, but this study also used this tool as dependent variable and did not report the constructed validity or the Cronbach alpha coefficient [20]. Insufficient data are available to validate the DASS-21’s psychometric properties in specific Thai populations, which could constitute considerable variation concerning sociocultural backgrounds and political differences among groups. To date, regarding the context of online learning, no research, concerning factor structures and convergent validity of DASS-21, has been conducted among Thai nursing students. Applying the original subscales scoring for all adulthood categories to only young adult age groups (approximately ages 18 to 26 years) without comprehending the instrument’s psychometric properties could lead to inaccurate conclusions [21]. This study aimed to examine the psychometric scale‐specific features of DASS-21 for Thai nursing students concerning an online learning situation during the COVID-19 outbreak. Materials and methods Study design and population This constituted cross-sectional research, obtaining data from one part of the larger multi-center study, aiming to assess the effects of online learning on the prevalence and factors associated with musculoskeletal disorders among Thai, Indonesian, Vietnamese, and Lao faculty members and students during the COVID-19 outbreak. After this study is completed, they recruit some samples and send them the survey of DASS-21. The target population of this study comprised Thai nursing students nationwide undertaken using a multistage sampling technique. Altogether, 96 nursing institutes in Thailand are spread across five regions. Using a simple random sampling technique, two of the five regions, the south and the northeast, were chosen in the first stage. In these areas, 37 nursing institutes are located. Then using a nonproportional stratified sampling technique, 15 nursing institutes were chosen. In addition, three nursing faculties from the Central Region were conveniently sampled, providing a total of 18 institutes. Totally, 5395 students were able to receive participant information sheets online from us. Prior to collecting data, administrators’ approval was obtained after a thorough description of the study’s objective. Before the survey began, a statement of consent was obtained from all participants by permitting only those who pressed "I consent" to go to the questionnaires. A total of 5136 participants indicated their willingness to join the study. Code numbers were created to protect students’ privacy. Finally, nonproportional stratified sampling was used on 4,618 undergraduate students, and 3705 became eligible respondents. Individual student data is only accessible to the authors of this study. These samples were employed to access study participants using an online web-based survey. Recruiting participants and collecting data occurred from April 2022 to June 2022. Study instruments The DASS-21 assesses depression, anxiety, and stress symptoms [10], and is divided into three subscales, each with seven items including depression (DASS 21-D), anxiety (DASS 21-A) and stress (DASS 21-S) (DASS 21S). The translation of this tool from English to Thai was carried out during the cross-culture translation procedure [19]. Each item is graded on a four-point Likert scale ranging from 0 (“did not apply to me at all”) to 3 (“applied to me a lot”). Because the DASS-21 is a shortened version of the DASS (42 items), the final score of each scale was multiplied by two before being compared with the original DASS scale. Higher scores and response values reflect greater levels of the condition being evaluated. In this study we used the Thai version of the DASS-21 with the original author’s permission [19]. The Cronbach’s alpha coefficients of depression, anxiety, and stress for The Thai version are 0.82, 0.78, and 0.69, respectively [19]. The Visual Analog Scale to Evaluate Fatigue Severity (VAS-F) [22] has 18 components all related to one’s perception of exhaustion. Each question asks respondents to place an “X" along a VAS line that runs between two extremes, such as "not at all fatigued" and "very tired," to identify what they are feeling right now. The score goes from 0 to 100 and is recorded using a vertical line of 10 cm. The line from "No fatigue" to the subject’s stated point indicating their level of fatigue, was measured to obtain the score; the higher the VAFS score, the greater the level of fatigue [23]. The Cronbach’s alpha for the fatigue subscale was 0.91 and the value of energy subscale was 0.94, respectively [22]. In addition, questions about general information of the participants, i.e., gender, age, study year, online learning, were included. Sample size calculation The sample size was calculated using the formula "sample size = number of items X number of participants," which is an extensively used formula in survey development research. We estimated the minimum sample size based on one item to ten participants [24]. Therefore, the minimum acceptable sample size, based on 21 items of DASS-21, was 210 respondents. However, our research enrolled 3,705 nursing students from 18 universities mainly located in south and northeast Thailand. Hence, larger sample size could provide more meaningful factor loadings and yield more generalizable results. The inclusion criteria for the participants were age at least 17 years, a nursing student at the institute during the study period more than six months and engaged in the online learning. Individuals who do not fill the administered questionnaire or submit an incompletely filled questionnaire such as responding to only a part of general information in the Thai Version of DASS-21, and nursing students with existing CMDs were excluded from this study. To avoid model overfitting, the exploratory (EFA) and confirmatory factor analyses (CFA) were organized on a random split of the total 3705 subjects in two group samples (group 1, n = 2000, and group 2, n = 1705). Statistical analysis All statistical analysis in this study was conducted using IBM SPSS and AMOS version 20. Descriptive statistics with means and standard deviation for continuous variables and counts and percentages for categorical data were used to describe the participant’s demographic characteristics. To investigate the number of components in the EFA for the DASS-21 measuring model, parallel analysis (based on principle component analysis) was undertaken using sample group 1. Then the structure of factors was investigated using principal axis factoring with varimax rotation. Factor loadings less than 0.5 were suppressed, and item cross loadings more than 0.2 were removed one at a time. Furthermore, factor loadings were used to calculate average variance extracted (AVE) and composite reliability (CR). Regarding the findings of the principal axis factoring, a CFA was applied to the remaining held-out participants. The measurement model was fitted using an unweighted least square estimate CFA, and model fit was evaluated using the cumulative fit index (CFI), adjusted goodness of fit index (AGFI), root-mean-square error of approximation (RMSEA), and Tucker-Lewis’s index (TLI) [19, 25, 26]. Likewise, Root Mean Square Error of Approximation (RMSEA) with a p-value less than 0.08 was considered to indicate a good model fit, so it was reported and used in this investigation for the sake of convention. Along with the CFA, the Kaiser-Meyer-Olkin (KMO) measure of sampling adequacy and the Bartlett’s test of sphericity were developed to provide additional construct validity evidence [27]. CR and Cronbach’s alpha were used to assess reliability. CR is acceptable when the values for the three subscales are greater than 0.6 [28]. Cronbach’s alpha was used to assess internal consistency reliability, and Cronbach’s alpha above 0.7 for all the subscales was considered to be an acceptable reliability [28]. In addition, the relationship between each of the DASS items and its own DASS subscale with that item removed is known as the corrected item-total correlations of the three subscales. We investigated the convergent validity of DASS-18 using the AVE. To indicate convergent validity, the AVE must be equal to or greater than 0.50, indicating that the construct’s variance accounts for more than 50% of its variation [26]. Furthermore, the discriminant validity determined whether the three indicators of depression, anxiety and stress domains were distinct factors from one another. Pearson’s correlation (r) lower than 0.85 among variables verified their discriminant validity [26] Pearson correlations were calculated to investigate the intercorrelations matrix, the temporal stability of DASS-18 subscale scores and the relationship between DASS-18 and VAS-F. Ethics considerations This study was examined and authorized by Walailak University’s institutional review board (Ref. No. WUEC-22-007-01) and the Center for Ethics in Human Research, Khon Kaen University (Ref. No. HE652094). Results General information of the participants The details of participant characteristics are described in Table 1. Most completing the questionnaire were females (94.2%) with a mean age of 20 (SD = 1.26) years. Almost two thirds of these participants (67.2%) were experiencing some semesters of online learning at the time of collecting data. 10.1371/journal.pone.0288041.t001 Table 1 Demographic characteristics of the participant. (n = 3705). Baseline characteristic Number Percent Sex  Male 215 5.8  Female 3490 94.2 Age (year)  18–19 1137 30.7  ≥20 2568 69.3 Mean (SD) 20.0 (1.26) Study year  1st 1313 35.4  2nd 1011 27.3  3rd 767 20.7  4th 614 16.6 Online learning  100% 1213 32.8  Some semester/subject 2492 67.2 Exploratory factor analysis After randomizing the 2000 participants for EFA, firstly, parallel analysis of the matrix indicated that a three-factor solution could be extracted. Secondly, the rotational factor loading matrix was statistically significant. Three factors having eigenvalues over one were created by the initial analyses of the Group 1 sample. To ascertain the factorial structure of DASS-21 and the underlying dimensions comprising its 21 items. The initial analysis revealed a three-factor structure that explained 69.31% of the original data’s variance. Three items (S8, S11, S12) from the stress scale were found to be loading on multiple factors; therefore, these items were removed from this analysis. The three factors resembled the original structure (9) with a reduced factor in stress component; however, the three-factor component (eigenvalues = 9.82; 1.74; and 1.23) was revealed by the scree plot and the eigenvalues higher than one requirement, and this model accounted for 71.31% of the variance. The result of the KMO test was 0.965 (χ2 = 30932; p<0.001), showing that the model was highly adequate. The factor loadings for each DASS- 18 item are shown in Table 2, with factor loadings >0.50 indicating acceptable loading (Table 2). 10.1371/journal.pone.0288041.t002 Table 2 Exploratory factor analysis of the DASS-18. Code Item Factor loading a DASS-18-D DASS-18-A DASS-18-S D3 I could not seem to experience any positive feeling at all. 0.756 D5 I found it difficult to work up the initiative to do things. 0.758 D10 I felt that I had nothing to look forward to. 0.790 D13 I felt downhearted and blue. 0.620 D16 I was unable to become enthusiastic about anything. 0.607 D17 I felt I wasn’t worth much as a person. 0.708 D21 I felt that life was meaningless. 0.711 A2 I was aware of dryness of my mouth. 0.853 A4 I experienced breathing difficulty. 0.863 A7 I experienced trembling. 0.843 A9 I was worried about situations in which I might panic and make a fool of myself. 0.856 A15 I felt I was close to panic. 0.849 A19 I was aware of the action of my heart in the absence of physical exertion. 0.597 A20 I felt scared without any good reason. 0.852 S1 I found it hard to wind down. 0.692 S6 I tended to over-react to situations. 0.798 S14 I was intolerant of anything that kept me from getting on with what I was doing. 0.729 S18 I felt that I was rather touchy. 0.745 KMO 0.956 Cronbach Alpha 0.825 0.968 0.900 Total 1.278 Cumulative % 71.311 a Extraction Method: Principal Component Analysis. Confirmatory factor analysis Three items from the stress scale were eliminated (the remaining 18 items of DASS, thus DASS-18). The DASS-18 measuring model, which included 18 items distributed across three components including DASS-18-A (7 items), DASS-18-D (7 items) and DASS-18-S (4 items) was fitted using an unweighted least square CFA. Based on the five specified fit criteria, the model demonstrated an acceptable fit to the data (CMIN/df = 3.082; p = 0.001; CFI = 0.98; RMSEA = 0.032; GFI = 0.98 and NFI = 0.99. The effect of the large sample size may have prevented the chi-square tests from providing acceptable assessments of model fit, whereas other indices indicated that these models remained well-fitted for the data. In addition, except for each factor-constraint item, so that no significant test could be archived, all model items were significantly loaded a long with their concurrent factors (all p-values <0.05) (Fig 1). 10.1371/journal.pone.0288041.g001 Fig 1 Structure model of the DASS-18 with standardized path coefficient. In all cases, the Pearson’s correlation coefficients between DASS-18-D, DASS-18-A and DASS-18-S presented moderate to remarkably elevated levels (0.52 to 0.92) indicating that these scales were moderately to highly discriminatory. Convergent validity AVE calculations showed all the DASS-18 subscales achieved a convergence effect (with the AVE of depression = 0.504; the AVE of anxiety = 0.674 and the AVE of stress = 0.551). Discriminant validity The magnitude of the correlations among depression, anxiety and stress domains determined the discriminant validity of the variables (Fig 1). The variables showed correlations (r) lower than 0.85 except the correlation between depression and stress domains (r = 0.91). Association of the DASS-18 scores among demographic characteristic and VAS-F The total scale of DASS-18 showed a statistically significant positive and fair to moderate association with the VAS-F total score, sex and online learning. Additionally, the DASS-18 total score showed a moderately positive significance correlated to VAS-F in the anticipated direction, confirming the association between higher levels of fatigue and higher levels of depression, anxiety, and stress (Table 3). 10.1371/journal.pone.0288041.t003 Table 3 Association of the DASS-18 scores with demographic characteristics of the Thai nursing student sample. Variable Total scale of DASS-18 p-value Age 0.151 0.763 Sex 0.103 <0.001 Online learning 0.451 <0.001 VAS-F 0.461 <0/001 Reliability analysis The CR of the three domains of DASS-18 ranging from 0.830 to 0.935 indicated evidence of acceptable reliability. Regarding Cronbach alpha values of 0.92 for the overall scale, 0.87 for depression, 0.79 for anxiety and 0.73 for stress, the DASS-18 exhibited adequate internal consistency reliability. Similarly, the internal consistency of this scale was good, as evidenced by the item-rest correlations for all three subscales being better than 0.3 and the corrected item-rest correlation for the entire scale ranging from 0.53 to 0.91 (Table 4). 10.1371/journal.pone.0288041.t004 Table 4 Reliability analysis of the DASS-18. Subscale Composite reliability Cronbach’s alpha Item test correlation Depression 0.876 0.87 0.65–0.77 Anxiety 0.935 0.79 0.66–0.91 Stress 0.830 0.73 0.53–0.63 Overall - 0.92 0.57–0.81 Product moment intercorrelations matrix values were determined between the three domains of DASS-18 and VAS-F. These intercorrelations values were found to be moderately strong the subscales of depression and anxiety showed the strongest intercorrelation among the three (r = 0.735), which was also statistically significant. These results could imply that the stress domain of DASS-18 moderately and positively correlated to VAS-F (r = 0.445) (Table 5). 10.1371/journal.pone.0288041.t005 Table 5 Intercorrelations matrix between domains of DASS-18 and VAS-F. Scales DASS-D DASS-A DASS-S VAS-F DASS-D 1.00 0.735* 0.737* 0.417* DASS-A 0.735* 1.00 0.708* 0.396* DASS-S 0.737* .708* 1.00 0.445* VAS-F 0.417* 0.396* 0.445* 1.00 * All correlations are significant at p <0.001 level (2-tailed) Discussion The purpose of this study was to evaluate the psychometric properties of DASS-21 among Thai nursing students experiencing online classes during the COVID-19 outbreak. For the results of the factorial construct validity of the DASS-18, a three-factor model showed satisfactory conformity to the psychometric construct of the DASS-21 original version [10], and these results support the fact that the DASS-18 instrument for this cohort contained 18 items spread across three components as follows: anxiety (seven items), depression (seven items) and stress (four items). The three factors were comparable to the structure found by prior studies exploring the psychometric features and generalization of the DASS-21 for use in Asian nations [19]. This investigation showed that the DASS-18 is a promising and psychometrically sound tool, ideally suited for determining the frequency and intensity of symptoms associated with negative affective states for these participants. Furthermore, the two-week temporal stability was good for all DASS-18 scale scores; in particular, the DASS-18 stress subscale showed the highest correlation values across time and they had a great internal consistency reliability, agreeing with our hypotheses. The consequences of reducing three items from the stress scale are the reasons for the lower Cronbach’s alpha coefficient of this scale than that of Lovibond and Lovibond’ s original version [10]. These differences might have resulted from the DASS-18 having fewer items because the quantity of items creates an impact on how Cronbach’s alpha is calculated [19]. According to our results, only minimal changes were observed between the original DASS-stress (seven items) and our DASS-stress (four items) scales. These disparities might be explained by how diverse culture’s view perception of some items that could be interpreted as besides the stress context cultural factors and the response of the participants may influence how individuals understand item of the DASS-stress scales, but not on the DASS-depression and DASS-anxiety scale as we found no significant cultural problem with these two scales and no concerns were noted regarding the EFA findings as demonstrated by the statistical results of this study. Therefore, the DASS-18 factor structure clearly demonstrated three factors, as in the original DASS-21 scale [10]. Likewise, one study reported that no invariances were discovered in their multi-group analysis across the six countries [19]. In addition, findings from this previous study on the correlations of the three subscales with those of other psychiatric instruments measuring similar constructs offered support for the validity of the DASS-18 subscales and were generally favorable [19]. Moreover, the depression and anxiety subscales of the DASS-18 exhibited specific relationships with the relevant measures of these disorders, indicating that using these constructs was appropriate. Cronbach’s alpha coefficient from our study revealed that total DASS-18 scores and its subscales exhibited good internal consistency. This coefficient ranged from good to excellent in prior studies comprising both nonclinical and clinical adult samples [2, 9, 10, 19, 21, 29–31]. Hence, the data collectively proved that the DASS-18 demonstrated strong internal consistency across a variety of demographics and languages. Moreover, the results of the item analysis indicated that the items in each scale had good discrimination indices (corrected item-total correction). These indices suggested that the DASS-18 Thai version items would be effective at distinguishing between high and low scorers on this scale. Related research has also revealed that this assessment tool provides a good item discrimination index [13, 18]. The relationships between demographic characteristics and DASS-18 scale scores were also investigated. This study found a weak positive statistically significant relationship between DASS-18 and sex. Despite the concerns about future endurance and competency aspect, female participants expressed more depression, anxiety, and stress than males. This may be because female nursing students usually have commitments outside of the classroom, such as taking care of their family members and performing chores [7, 32]. Our results indicated that online learning moderately, positively correlated to the total DASS-18 score because high standards for performance, learning habits, and training may negative impact students’ mental health [7]. Similarly, clinical courses in nursing programs call for specialized cognitive, emotional, and psychomotor abilities typically following specialized theoretical courses. Because of being unable to take part in clinical settings, these students felt as though they were missing out on a great opportunity to acquire these abilities [6, 20]. Thus, these students may have felt unprepared for learning in a clinical setting due to the extremely brief on campus learning time before lockdown, and the pandemic made it more difficult for nursing students to advance in their practical training [6]. When lockdowns ended, nursing students had greater opportunity to contract an illness by themselves or face patients with COVID-19 experiencing significant effects [5]. The internal consistency of the DASS-18 was adequate and consistent with the related Asian research [7, 19]. The Thai version’s convergent validity is supported by favorable correlations with the Beck Depression Inventory (BDI), the Beck Anxiety Inventory (BAI); correlations in this direction were anticipated to measure the same construct [19]. These results demonstrated the validity and reliability of the Thai DASS-18 version as a tool for measuring negative emotional states. This indicated that this scale could prove beneficial for screening CMDs among clinical undergraduate students including nursing students. The convergent validity of the DASS-18 was examined using the AVE calculation of all three subscales. The results revealed that all sub-scales’ AVE were greater than 0.50, corresponding to the convergent validity acceptance criteria. These findings were also compatible with the findings of a study that aimed to validate the DASS-21 among Vietnam students in an e-learning environment [7]. Regarding the discriminant validity, factors of this stress subscale also highly correlated to each other, which were higher than the values suggested by Hu and Bentler [26]. These higher correlations indicated significant overlapping in the content of the DASS-18 scales, indicating a general construct, such as affective distress. One related study also reported a higher correlation among these subscales [13]. When comparing depression, anxiety and stress scales, anxiety items had higher factor loadings, eigenvalues, and percentage of variation than the other domains. Depression and anxiety continued to have the highest inter-correlations, with a value of 0.708 indicating significant overlap between the two domains. Despite the overlap between domains, they could still be separated. An extraordinarily strong and positive association was noted between these domains. The Thai nursing students’ symptoms of stress, anxiety and depression were all positively connected, according to these positive correlation values. The DASS-18’s correlation coefficients showed beneficial correlations between the two instruments in this regard. Likewise, these coefficients also showed that the subjects’ anxiety and depression were present at the same time. The DASS-18 was thus shown to measure depression and anxiety among the responders in a simultaneous and unique manner. These findings were in line with studies in other countries [21, 29]. Strengths and limitations The strength of this study is the fact that the structure and psychometric features of the DASS-21 were examined for the first time in a large sample of undergraduate nursing students in Thailand. Because the participant-to-questionnaire-item ratio was satisfactory, the prerequisites for component analysis were met, and bias resulting from the number of observations was reduced. Our study encountered limitations regarding the nursing students comprising our subjects. They could not accurately be generalized to other nonclinical undergraduate students due to their diverse qualities because they may be privileged in terms of socioeconomic status, freedom, and health. The study was cross-sectional; hence, the data were unable to show test-retest reliability over time. The study was limited in terms of criterion validity because we did not test any other parameters besides VAS-F. Conclusion The study ‘s main findings demonstrate that the DASS-18 is a valid instrument for detecting CMDs among Thai nursing students enrolled in online courses during the COVID-19 outbreak. The three-factor structure with 18 items proposed in the initial study was supported by the findings. Therefore, the availability of the DASS-18’s psychometric features will enhance performance of Thai psychologists and researchers in effectively screening the population of undergraduate nursing students for CMDs at tertiary institutions. Supporting information S1 Data (XLSX) Click here for additional data file. The authors thank all nursing institutions for supporting students’ data collection. The research collaborators at all involved nursing institutes are thanked by the authors for helping with sample recruitment and data gathering. All nursing students joining this study are gratefully acknowledged. 10.1371/journal.pone.0288041.r001 Decision Letter 0 Khraisat Omar M Academic Editor © 2023 Omar M Khraisat 2023 Omar M Khraisat https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Submission Version0 10 Apr 2023 PONE-D-22-31148Ref. KPB.B 1900/225/2565 11 December, 2022Validation of the depression, anxiety, and stress scales (DASS-21): among Thai nursing students in the online learning environment during the COVID-19 outbreak: A multi-center study.PLOS ONE Dear Dr. summart, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please submit your revised manuscript by May 10,2023. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. Please include the following items when submitting your revised manuscript:A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'. If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter. If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols. We look forward to receiving your revised manuscript. Kind regards, Omar M Khraisat, Associate Professor Academic Editor PLOS ONE Journal requirements: When submitting your revision, we need you to address these additional requirements. 1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf. 2. During your revisions, please note that a simple title correction is required: Please remove the text "Ref. KPB.B 1900/225/2565 11 December, 2022" from the title on the online submission information. 3. Please provide additional details regarding participant consent. In the ethics statement in the Methods and online submission information, please ensure that you have specified what type you obtained (for instance, written or verbal, and if verbal, how it was documented and witnessed). If your study included minors, state whether you obtained consent from parents or guardians. If the need for consent was waived by the ethics committee, please include this information. 4. Thank you for stating the following in the Acknowledgments/ Funding Section of your manuscript: “The Walailak University's Individual Research Grants provided funding for the study (Grant Number WU-IRG-65-015).” We note that you have provided funding information that is not currently declared in your Funding Statement. However, funding information should not appear in the Acknowledgments section or other areas of your manuscript. We will only publish funding information present in the Funding Statement section of the online submission form. Please remove any funding-related text from the manuscript and let us know how you would like to update your Funding Statement. Currently, your Funding Statement reads as follows: “The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.” Please include your amended statements within your cover letter; we will change the online submission form on your behalf. 5. In your Data Availability statement, you have not specified where the minimal data set underlying the results described in your manuscript can be found. PLOS defines a study's minimal data set as the underlying data used to reach the conclusions drawn in the manuscript and any additional data required to replicate the reported study findings in their entirety. All PLOS journals require that the minimal data set be made fully available. For more information about our data policy, please see http://journals.plos.org/plosone/s/data-availability. Upon re-submitting your revised manuscript, please upload your study’s minimal underlying data set as either Supporting Information files or to a stable, public repository and include the relevant URLs, DOIs, or accession numbers within your revised cover letter. For a list of acceptable repositories, please see http://journals.plos.org/plosone/s/data-availability#loc-recommended-repositories. Any potentially identifying patient information must be fully anonymized. Important: If there are ethical or legal restrictions to sharing your data publicly, please explain these restrictions in detail. Please see our guidelines for more information on what we consider unacceptable restrictions to publicly sharing data: http://journals.plos.org/plosone/s/data-availability#loc-unacceptable-data-access-restrictions. Note that it is not acceptable for the authors to be the sole named individuals responsible for ensuring data access. We will update your Data Availability statement to reflect the information you provide in your cover letter. 6. We note that you have indicated that data from this study are available upon request. PLOS only allows data to be available upon request if there are legal or ethical restrictions on sharing data publicly. For more information on unacceptable data access restrictions, please see http://journals.plos.org/plosone/s/data-availability#loc-unacceptable-data-access-restrictions. In your revised cover letter, please address the following prompts: a) If there are ethical or legal restrictions on sharing a de-identified data set, please explain them in detail (e.g., data contain potentially sensitive information, data are owned by a third-party organization, etc.) and who has imposed them (e.g., an ethics committee). Please also provide contact information for a data access committee, ethics committee, or other institutional body to which data requests may be sent. b) If there are no restrictions, please upload the minimal anonymized data set necessary to replicate your study findings as either Supporting Information files or to a stable, public repository and provide us with the relevant URLs, DOIs, or accession numbers. For a list of acceptable repositories, please see http://journals.plos.org/plosone/s/data-availability#loc-recommended-repositories. We will update your Data Availability statement on your behalf to reflect the information you provide. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Partly ********** 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: No ********** 3. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: No ********** 4. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: No ********** 5. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: 1. Under study design & Population: It is not clear how they recruit the participants in their study since the sample was taken from a larger multi-center survey, and how they randomize them. 2.Do the survey was part of the larger study, or after the larger study completed they recruit the sample and send them the survey of DASS-21 2. "To interpret these results is comparable to the original version of DASS-41 that calculated from the total scores for each sub-scale multiplying by two". This statement is not clear. & why they have used the 21 items scale since the original was 41 items? 3. Reference number 24 is retracted. 4. Based on what you have enrolled this number of participant (3705)? and you have mentioned that you need 5 – 10 participants for each item. 5. The exclusion criteria are not clear in the manuscript. 6. Fatigue (VAS-F) is different construct than anxiety and depression. So how it was used to test the convergent validity of the DASS-18. 7. It is not clear how randomization of the participants was done? 8. It was mentioned that the parellel analysis revealed a single factor, then a 3 factor solution was created. how this was run? 9. What was the factor loading for the deleted items and in which factors they loading(the rule is to retain items if they had a factor loading of 0.4 or more). 10. Did the total variance changed after you remove the three factors? 11. The title of Table 2 need to be changed to "The title of the table should be Exploratory Factor Analysis of the DASS-18" 12. in page 11 under the tittle Confirmatory factor analysis, the term "subscales" is used instead of "Items".. there is a big difference between both. 13. What was Composite Reliability (CR) of the three factors as an evidence of reliability. 14. What was the Average Variance Extracted (AVE) for the scales ? (this is considered a measure of convergent validity) 15. What is the relation of gender to convergent validity? Gender is not a scale. how you consider is an evidence of convergent validity? 16. Table 3 has a lot of errors & empty cells. besides, this is a correlation table not a Convergent and discriminant validity for the subscale of the DASS-18. 17. How did you measure the variable "Online Learning". it was mentioned in table 3. 18. some non scientific terms are used such as "directly linked".. "values were discovered to exist"." comparable discoveries" 19. I am not sure why table 5 was reported. it is a correlation table. they have already run the factor analysis. 20. How the temporal stability of the tool was measure. " the term is mentioned in page 13 under "Discussion". 21. There are some typing and grammatical errors in the manuscript. 22. How did the authors know that female had more depression? We can’t know that by simple running correlation. You need to do a T-test 23. The authors have mentioned in the discussion that "no effect on both the DASS-depression and DASS-anxiety scales as we found no significant cultural problems with those two scales and there was no concern with the EFA findings as demonstrated by the statistical results". I think this couldn’t attributed to cultural factors only. This depends on the responses of the participants 24. The authors have mentioned that "The Thai version's convergent validity is supported by favorable correlations with VAS-F dimensions; correlations in this direction were anticipated which were expected to measure the same construct" Actually they are measuring different constructs, so they came up with this conclusion? 25. the authors have reported that there is an evidence of concurrent validity but it is not clear how it was measured (278 anxiety and depression are used in the same tool, so it can't be considered a concurrent validity. ********** 6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: No ********** [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step. 10.1371/journal.pone.0288041.r002 Author response to Decision Letter 0 Submission Version1 1 May 2023 For the reviewser' scomments, I am very appreciate for all comments because I have some error before you kindly comment our manuscript. Thanks for your good comments for me. Attachment Submitted filename: Response to Reviewers.docx Click here for additional data file. 10.1371/journal.pone.0288041.r003 Decision Letter 1 Khraisat Omar M Academic Editor © 2023 Omar M Khraisat 2023 Omar M Khraisat https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Submission Version1 8 Jun 2023 PONE-D-22-31148R1Validation of the depression, anxiety, and stress scales (DASS-21) among Thai nursing students in the online learning environment during the COVID-19 outbreak: A multi-center study.PLOS ONE Dear Dr. summart, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please submit your revised manuscript by Jul 23 2023 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. Please include the following items when submitting your revised manuscript:A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'. If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter. If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols. We look forward to receiving your revised manuscript. Kind regards, Omar M Khraisat, Associate Professor Academic Editor PLOS ONE Journal Requirements: Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation. Reviewer #2: All comments have been addressed Reviewer #3: All comments have been addressed ********** 2. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #2: Yes Reviewer #3: Yes ********** 3. Has the statistical analysis been performed appropriately and rigorously? Reviewer #2: Yes Reviewer #3: Yes ********** 4. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #2: Yes Reviewer #3: Yes ********** 5. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #2: Yes Reviewer #3: Yes ********** 6. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #2: Thank you for the opportunity to review this manuscript. The article reports the validation of the Depression, Anxiety, and Stress Scales (DASS-21) among Thai nursing students in the online learning environment during the COVID-19 outbreak. The topic holds significant importance for the nursing profession, considering the global impact of the COVID-19 pandemic. I particularly appreciate the inclusion of universities from various regions of Thailand in their study. I commend the authors for undertaking this research. Please see my comments below for strengthening the manuscript: Introduction: The introduction section could be written with more clarity and focus on the research gap. Some statements are too generic and require context and clarification of terms. I have detailed them below: • The reference to Lee et al (2019) was used to support the statement about low performance at work or school, disruptions in social life, and even suicide, but the reference is a study evaluating the Depression Anxiety Stress Scales, which is not directly relevant. It would be helpful to provide more specific and relevant references to support these claims. • The statement about "more than a third of nursing students" and almost 'one half of these students' would be unclear without the total number of nursing students in the context of the study. Clarifying the total number of nursing students would provide better context. • It would be beneficial to provide a clear definition of 'remote learning' or 'online learning,' whichever terms the authors choose, to establish the context. Additionally, the terms "high intentions," "extensive training and learning processes" need further clarification and explanation. • The article mentions a research article explaining the high risk of infection exposure and fear of transmitting diseases among students, but it is not clear how this relates to the study's context of 'remote learning'. The connection between remote learning and these factors needs to be clearly established. • The sentence in line 42-43 requires evidence to support the claim made. It would be beneficial to provide supporting references or data to strengthen this statement. • There should be a brief explanation of DASS, its psychometric properties, and the difference between DASS-21 and the original DASS scale. Justifying the use of DASS-21 in this study would enhance the manuscript. • It is important to define the young adult age group being referred to in the study. Clarifying the specific age range would eliminate ambiguity and improve the precision of the research. • Considering the Thai context during the COVID-19 outbreak/pandemic, it would be valuable to include relevant information about the situation in Thailand, particularly during the data collection phase from April to June 2022. Providing contextual information would enhance the understanding of the study's findings. Study instruments: I was unsure how the process of translating the original version into Thai was conducted, as the reference was to a DASS Brunei version. It would be helpful to provide information on who conducted the translation, whether there was any back-translation, and the measures taken to ensure there was no loss of meaning in the translation and to ensure consistency and validity. Additionally, information on the reliability and validity of the selected instruments, including the VAS-F scale, should be provided. Was there any pilot testing of the translated version? Sample size calculation: Information on the sample could have been better. Who were these nursing students? What kind of remote learning did they engage in, how many hours, and what courses were included? How were they recruited? It would also be helpful to clarify whether students with existing CMDs (Common Mental Disorders) were excluded or not. Line 130 - (group 1, n= 2,000, and group 2, n= 1,706). The total should be 3,706. Please verify this. Statistical analysis: Can you include the statistical software used? I wasn't clear which items were removed and how the study ended up using DASS-18. It was only explained later on under the subheading "Confirmatory factor analysis." It would be helpful to signpost the reader by mentioning that this would be discussed later on. The results and discussion sections are generally well-written. However, the statement in Line 274-276 should elaborate more on cultural factors and draw on relevant literature to support the discussion. Additionally, in relation to this statement, I wasn't sure what was meant by "no significant cultural problems." It would be beneficial to provide further clarification or explanation to ensure understanding. Reviewer #3: (No Response) ********** 7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #2: No Reviewer #3: Yes: Emmanuel Z. Chona ********** [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step. 10.1371/journal.pone.0288041.r004 Author response to Decision Letter 1 Submission Version2 13 Jun 2023 Thank you for all of your comment to improve our manuscript. We attemp to edit and clearify all of the statements that you recommends however our revised manuscript is not completely edited. Please accept our apologize. We remain accetable for all of your suggestion. Attachment Submitted filename: Response to Reviewers.docx Click here for additional data file. 10.1371/journal.pone.0288041.r005 Decision Letter 2 Khraisat Omar M Academic Editor © 2023 Omar M Khraisat 2023 Omar M Khraisat https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Submission Version2 19 Jun 2023 Validation of the depression, anxiety, and stress scales (DASS-21) among Thai nursing students in the online learning environment during the COVID-19 outbreak: A multi-center study. PONE-D-22-31148R2 Dear Dr., We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org. If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Omar M Khraisat, Associate Professor Academic Editor PLOS ONE Additional Editor Comments (optional): Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation. Reviewer #2: All comments have been addressed ********** 2. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #2: No ********** 3. Has the statistical analysis been performed appropriately and rigorously? Reviewer #2: Yes ********** 4. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #2: Yes ********** 5. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #2: Yes ********** 6. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #2: I am pleased with the comprehensive revisions made in response to the comments. I would like to note that there is a discrepancy in line 144-5, where the total number is stated as 3,706 instead of 3,705 as mentioned elsewhere in the manuscript. Please double-check this inconsistency. ********** 7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #2: No ********** 10.1371/journal.pone.0288041.r006 Acceptance letter Khraisat Omar M Academic Editor © 2023 Omar M Khraisat 2023 Omar M Khraisat https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 22 Jun 2023 PONE-D-22-31148R2 Validation of depression, anxiety, and stress scales (DASS-21) among Thai nursing students in an online learning environment during the COVID-19 outbreak: a multi-center study. Dear Dr. Summart: I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department. If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org. If we can help with anything else, please email us at plosone@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Dr. Omar M Khraisat Academic Editor PLOS ONE ==== Refs References 1 Santomauro DF , Herrera AMM , Shadid J , Zheng P , Ashbaugh C , Pigott DM , et al . Global prevalence and burden of depressive and anxiety disorders in 204 countries and territories in 2020 due to the COVID-19 pandemic. The Lancet. 2021;398 (10312 ):1700–12. doi: 10.1016/S0140-6736(21)02143-7 34634250 2 Lee E-H , Moon SH , Cho MS , Park ES , Kim SY , Han JS , et al . The 21-item and 12-item versions of the depression anxiety stress scales: psychometric evaluation in a Korean population. Asian nursing research. 2019;13 (1 ):30–7. doi: 10.1016/j.anr.2018.11.006 30503903 3 Baloran ET . Knowledge, attitudes, anxiety, and coping strategies of students during COVID-19 pandemic. Journal of loss and trauma. 2020;25 (8 ):635–42. doi: 10.1111/jocn.15634 4 Aguilar MV , Torres G . Making Sense of Online Classes during Quarantine due to the COVID-19 Pandemic: Students’ Perceptions from a Philippine University. Asia Social Issues. 2021;14 (4 ):248066. https://so06.tci-thaijo.org/index.php/wjss 5 Bai W , Xi H-T , Zhu Q , Ji M , Zhang H , Yang B-X , et al . Network analysis of anxiety and depressive symptoms among nursing students during the COVID-19 pandemic. Journal of affective disorders. 2021;294 :753–60. doi: 10.1016/j.jad.2021.07.072 34375200 6 Masha’al D , Rababa M , Shahrour G . Distance learning–related stress among undergraduate nursing students during the COVID-19 pandemic. Journal of Nursing Education. 2020;59 (12 ):666–74. doi: 10.3928/01484834-20201118-03 33253395 7 Lan HTQ , Long NT , Hanh NV . Validation of Depression, Anxiety and Stress Scales (DASS-21): Immediate Psychological Responses of Students in the E-Learning Environment. International Journal of Higher Education. 2020;9 (5 ):125–33. 8 Savitsky B , Findling Y , Ereli A , Hendel T . Anxiety and coping strategies among nursing students during the covid-19 pandemic. Nurse education in practice. 2020;46 :102809. doi: 10.1016/j.nepr.2020.102809 32679465 9 Thiyagarajan A , James TG , Marzo RR . Psychometric properties of the 21-item Depression, Anxiety, and Stress Scale (DASS-21) among Malaysians during COVID-19: a methodological study. Humanities and Social Sciences Communications. 2022;9 (1 ):1–8. doi: 10.1057/s41599-022-01229-x 35789924 10 Lovibond PF , Lovibond SH . The structure of negative emotional states: comparison of the Depression Anxiety Stress Scales (DASS) with the Beck Depression and Anxiety Inventories. Behaviour research and therapy. 1995;33 (3 ):335–43. doi: 10.1016/0005-7967(94)00075-u 7726811 11 Pooravari M , Dehghani M , Salehi S , Habibi M . Confirmatory factor analysis of Persian version of Depression, Anxiety and Stress (DASS-42): Non-clinical sample. Razavi International Journal of Medicine. 2017;5 (4 ). 12 Makara-Studzińska M , Tyburski EM , Załuski M , Adamczyk K , Mesterhazy J , Mesterhazy A . Confirmatory factor analysis of three versions of the depression anxiety stress scale (DASS-42, DASS-21, and DASS-12) in Polish adults. Frontiers in psychiatry. 2021:2342 . doi: 10.3389/fpsyt.2021.770532 35058818 13 Ali AM , Green J . The psychometric properties of the Depression Anxiety Stress Scale-21 (DASS-21) Bangla version. Substance abuse treatment, prevention, and policy. 2019;14 (1 ):1–8. doi: 10.1016/j.actpsy.2022.103509 30606266 14 Abd Majid HS , Abd Hamid HS , Alwi A , Sulaiman MK . Psychometric Properties of the English Version of DASS in a Sample of Malaysian Nurses. Jurnal Psikologi Malaysia. 2019;33 (1 ). 15 Nanthakumar S , Bucks RS , Skinner TC , Starkstein S , Hillman D , James A , et al . Assessment of the Depression, Anxiety, and Stress Scale (DASS-21) in untreated obstructive sleep apnea (OSA). Psychological Assessment. 2017;29 (10 ):1201. doi: 10.1037/pas0000401 27936819 16 Apóstolo JLA , Tanner BA , Arfken CL . Confirmatory factor analysis of the Portuguese Depression Anxiety Stress Scales-21. Revista latino-americana de enfermagem. 2012;20 :590–6. doi: 10.1590/s0104-11692012000300022 22991123 17 Henry JD , Crawford JR . The short‐form version of the Depression Anxiety Stress Scales (DASS‐21): Construct validity and normative data in a large non‐clinical sample. British journal of clinical psychology. 2005;44 (2 ):227–39. doi: 10.1348/014466505X29657 16004657 18 Teo YC , Yusuf A , Alice Lim WP , Ghazali NB , Abd Rahman H , Lin N , et al . Validation of DASS-21 among nursing and midwifery students in Brunei. Journal of Public Health. 2019;27 (3 ):387–91. doi: 10.1007/s10389-018-0947-z 19 Oei TP , Sawang S , Goh YW , Mukhtar F . Using the depression anxiety stress scale 21 (DASS‐21) across cultures. International Journal of Psychology. 2013;48 (6 ):1018–29. doi: 10.1080/00207594.2012.755535 23425257 20 Nimkuntod P , Uengarpon N , Benjaoran F , Pinwanna K , Ratanakeereepun K , Tongdee P . Psychometric properties of depression anxiety and stress in preclinical medical students. J Med Assoc Thai. 2016;99 :S111–S7. 29901964 21 Le MTH , Tran TD , Holton S , Nguyen HT , Wolfe R , Fisher J . Reliability, convergent validity and factor structure of the DASS-21 in a sample of Vietnamese adolescents. PloS one. 2017;12 (7 ):e0180557. doi: 10.1371/journal.pone.0180557 28723909 22 Lee KA , Hicks G , Nino-Murcia G . Validity and reliability of a scale to assess fatigue. Psychiatry research. 1991;36 (3 ):291–8. doi: 10.1016/0165-1781(91)90027-m 2062970 23 Tseng BY , Gajewski BJ , Kluding PM . Reliability, responsiveness, and validity of the visual analog fatigue scale to measure exertion fatigue in people with chronic stroke: a preliminary study. Stroke research and treatment. 2010;2010. doi: 10.4061/2010/412964 20700421 24 Suresh K , Chandrashekara S . Sample size estimation and power analysis for clinical research studies. Journal of human reproductive sciences. 2012;5 (7 ):7–13. doi: 10.4103/0974-1208.97779 22870008 25 Shevlin M , Miles JN . Effects of sample size, model specification and factor loadings on the GFI in confirmatory factor analysis. Personality and Individual differences. 1998;25 (1 ):85–90. doi: 10.1016/S0191-8869(98)00055-5 26 Lt Hu , Bentler PM . Cutoff criteria for fit indexes in covariance structure analysis: conventional criteria versus new alternatives. Structural equation modeling: a multidisciplinary journal. 1999;6 (1 ):1–55. doi: 10.1080/10705519909540118 27 Kaiser HF . An index of factorial simplicity. psychometrika. 1974;39 (1 ):31–6. doi: 10.1007/BF02291575 28 Kline P. Handbook of psychological testing: Routledge; 2013. 29 Coker A , Coker O , Sanni D . Psychometric properties of the 21-item depression anxiety stress scale (DASS-21). African Research Review. 2018;12 (2 ):135–42. 10.4314/afrrev.v12i2.13 30 Musa R , Maskat R . Psychometric properties of depression anxiety stress scale 21-item (DASS-21) malay version among a big sample population. Mediterranean Journal of Clinical Psychology. 2020;8 (1 ). doi: 10.6092/2282-1619/mjcp-2269 31 Ahmed O , Faisal RA , Alim SMAHM , Sharker T , Hiramoni FA . The psychometric properties of the Depression Anxiety Stress Scale-21 (DASS-21) Bangla version. Acta Psychologica. 2022;223 :103509. doi: 10.1016/j.actpsy.2022.103509 35065529 32 Beumeler LFE , Waarsenburg E , Booij S , Scheurink A , Hoenders H . Evaluation of a lifestyle intervention program in primary care on physical and mental health and quality of life of cancer survivors: a pilot study. European Journal of Integrative Medicine. 2018;23 :1–5. doi: 10.1016/j.eujim.2018.08.007