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Comprehensive Psychiatry 54 (2013) 398–405www.elsevier.com/locate/comppsych

Evaluation of the psychometric properties of the Self-ReportingQuestionnaire (SRQ-20) in a sample of Vietnamese adults

Kelcey J. Strattona,b,⁎, Steven H. Aggenb, Lisa K. Richardsonc, Ron Aciernod,e,Dean G. Kilpatrickd, Mario T. Gabouryf, Trinh Luong Trang, Lam Tu Trungh,

Nguyen Thanh Tami, Tran Tuanj, La Thi Buoi j, Tran Thu Haj,Tran Duc Thachj, Ananda B. Amstadterb

aHunter Holmes McGuire VA Medical CenterbVirginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University

cMurdoch UniversitydMedical University of South Carolina, Department of Psychiatry and Behavioral Sciences

eRalph S. Johnson VA Medical CenterfHenry C. Lee College of Criminal Justice and Forensic Sciences, University of New Haven

gHealth Department of Da Nang CityhDa Nang Mental Health Hospital

iVietnam Veterans of America FoundationjResearch and Training Center for Community Development

Abstract

Purpose: There are significant gaps in the literature on the prevalence of mental health problems and associated needs in Vietnam. Athorough understanding of culture-specific expressions of psychiatric distress is vital for the identification of the mental health needs of acommunity, and more research on the development and evaluation of culturally-sensitive mental health assessments is warranted. This studyaims to evaluate the psychometric properties of the World Health Organization 20-item Self-Reporting Questionnaire (SRQ-20) in anepidemiologic study of Vietnamese adults.Methods: A latent variable modeling approach investigated the underlying factor structure of the SRQ-20 items. Exploratory factor analysis(EFA) and confirmatory factor analysis (CFA) were conducted on SRQ-20 item-level data gathered from 4980 participants.Results: Based on scree plots and EFA results, two latent structures were deemed plausible and were subsequently subjected to furthermodeling. A bi-factor model (BFM) and a correlated three-factor model solution (Negative Affect, Somatic Complaints, and Hopelessness)provided reasonable fits. The BFM specifies a single dominant General Distress factor (all SRQ-20 items) with orthogonal group factors forthe subsets of items: Negative Affect (9 items), Somatic Complaints (8 items), and Hopelessness (3 items). This model fit the data as well orbetter than the three-factor model. Results also showed differences in endorsement rates of SRQ-20 items among males and females.Conclusions: Study results provide an evaluation of the psychometric properties of a commonly used screening tool and offer insight into thepresentation of mental distress in a representative sample of Vietnamese adults.Published by Elsevier Inc.

Conflict of interest statement: The authors declare that they have noconflict of interest.

Writing of this manuscript was supported by the Office of AcademicAffiliations, Advanced Fellowship Program in Mental Illness Research andTreatment, Department of Veterans Affairs.

⁎ Corresponding author. Hunter Holmes McGuire VA Medical Center,1201 Broad Rock Blvd. (116-B), Richmond, VA 23249. Tel.: +1 804 6755000x2432; fax: +1 804 675 6853.

E-mail address: Kelcey.Stratton@va.gov (K.J. Stratton).

0010-440X/$ – see front matter. Published by Elsevier Inc.http://dx.doi.org/10.1016/j.comppsych.2012.10.011

1. Introduction

Mental health disorders have emerged as a growing areaof interest and concern for global public health. Despite theincreased attention from agencies such as the World HealthOrganization (WHO) and Centers for Disease Control [1,2],there remain significant gaps in the literature on theepidemiology of mental health disorders in many developingcountries. In particular, estimated prevalence rates of mentaldisorders in South-East Asian countries are significantly

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lower than in Western nations [3–5], raising some questionsabout the ability of standard psychiatric assessment tools tocapture mental health presentations in these populations [4].The goal of the present study is to better understandpsychiatric symptom reporting and to evaluate a commonlyused mental health assessment tool as part of a larger surveyof mental health needs in Vietnam.

In the past two decades, several large-scale epidemiolog-ical surveys of cross-national mental health have raisedawareness of age of onset, lifetime prevalence, and projectedlifetime risk of mental disorders [6–8]. Results indicate thatmental disorders pose a significant burden to individuals, totheir families, and to society due to both the high prevalenceand associated functional disability [9,10]. Given theseconcerns about psychiatric disorders, the WHO has empha-sized mental health as a public health priority, and manycountries have begun to adopt policies to improve the accessto mental health resources and enhance the quality ofpsychiatric care. Despite these efforts, significant barriers tomental health knowledge, treatment, and public policycontinue to exist worldwide [1,11]. Low and lower-middleincome countries often have significant gaps in mental healthdiagnosis reporting, fewer mental health workers, and alower median percentage of health expenditures dedicated tomental health. Further, many of these countries lackcommunity mental health care, and most mental healthtreatments, including psychotropic medications and psycho-social interventions, are widely unavailable in primary careclinics [1,12,13]. In order to make the most efficient use ofthese limited resources and provide targeted interventions forpsychiatric disorders, it is critical to establish appropriatescreening tools for accurate mental health assessment.

One historically understudied country with regard topsychiatric distress, Vietnam, has received recent attention.The Vietnamese government and several non-governmentalorganizations (NGOs) have aimed to improve the mentalhealth system and to move toward community managementand detection of mental illness [12]. To date, information onmental health needs and prevalence rates in Vietnam islimited to reports from a small number of datasets [5,14,15],as well as reports from our group using the present data [16–18]. Of note, Steel and colleagues' surveys of mental healthamong Vietnamese, Vietnamese–Australian, and Australiansamples found much lower prevalence of mental disordersamong the Vietnamese and Vietnamese–Australian sampleswhen using the Composite International Diagnostic Instru-ment [5,19]. The inclusion of a culturally-derived assessmenttool, the Phan Vietnamese Psychiatric Scale, resulted inincreased identification of psychiatric distress in both theVietnamese and Vietnamese–Australian samples, highlight-ing the importance of culturally sensitive assessment [5].Thanh et al.'s study of lifetime and 12-month prevalencerates of suicidal ideation also yielded lower reported rates ofpsychiatric symptoms in Vietnam than in Western nations[15]. Conclusions from these studies pose questionsregarding the appropriateness of using standard, Western-

derived assessments of mental health, as they may notadequately capture prevailing modes of symptom expres-sion. Indeed, few psychiatric symptom reporting measureshave been validated in Vietnamese community samples.Therefore, it is important to determine whether existingmeasures of mental distress can be adapted for use in thispopulation, and if so, to determine how these instrumentsfare in terms of assessing culturally unique indicators ofmental distress. For nations such as Vietnam to develop morecomprehensive mental health programs in the future, theaccurate measurement of psychological phenomena will beof critical importance.

This study aims to evaluate the psychometric properties ofthe WHO 20-item Self-Reporting Questionnaire (SRQ-20)in an epidemiologic survey of Vietnamese adults. The SRQ-20 was developed as an instrument to screen for generalpsychiatric disturbances [20], and it has been found to bereliable, valid, and adaptable for screening mental disordersin many countries. In Vietnam, the SRQ-20 has demonstrat-ed acceptable validity as a screening tool when compared toin-depth psychiatric interviews, providing preliminaryevidence that this instrument is an appropriate assessmentof symptom expression in Vietnam [14,21]. These studiesrelied on the total SRQ-20 score and the determination of“caseness,” and more study is needed to understand thestructural validity of the scale; that is, how the individualSRQ-20 items map onto underlying mental health constructs.Previous studies using the SRQ-20 in different countrieshave found important differences in the factor structure ofthe scale [22–25], suggesting that the screening items maydifferentially relate to culturally-salient aspects of mentalhealth. To date, there have been no studies investigating thefactor structure of the SRQ-20 in Vietnamese adults, andthus it is unknown how the items of this instrumentdistinguish underlying mental health constructs within thiscultural context. The current study examines item charac-teristics of the SRQ-20 using a latent variable common factormodeling approach in order to better understand therelationship between the individual items and the latentmental health constructs that these items assess. A betterunderstanding of cultural expressions of mental distress andthe validation of culturally-relevant mental health screeningtools may improve diagnostic efficacy, enhance riskassessment, and provide valuable information on mentalhealth symptom profiles in Vietnam.

2. Methods

In 2006, the Da Nang Department of Health and theKhanh Hoa Health Service, in cooperation with severalNGOs (i.e., the Research and Training Centre for Commu-nity Development (RTCCD), the Vietnam Veterans ofAmerica Foundation (VVAF), and the Atlantic Philanthro-pies) conducted a mental health needs assessment ofresidents in their respective provinces. This epidemiological

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study sought to obtain prevalence data regarding generalmental health problems using the SRQ-20. A full descriptionof the data collection methods has been previously described[18]. The initial data collection occurred between August andOctober of 2006, and was interrupted by typhoon Xangsane,which struck Da Nang province on October 26th. Thecurrent study examines data collected before the typhoonstruck the province.

2.1. Participants

Participants were recruited through a four stage clustersampling strategy. First, 30 communes were randomlyselected from each province. Communes are administrativesubdivisions of provinces, which are the highest structuralmanagement authority in Vietnam below the government.Second, three hamlets, or small communities of about 1000people, were randomly chosen at each selected commune.Third, 30 households were randomly selected at each chosenhamlet, and finally, all household members aged 11 and olderwere selected for potential study. The final sample for thecurrent study included 4980 adults aged 18 years or older.

Vietnamese lay interviewers from Da Nang and KhanhHoa received six days of training, which included informa-tion regarding the purpose of the study, the research design,and the specific questionnaires, an interview trainingprotocol, and education on depression, anxiety, alcoholabuse, sleep problems, chronic fatigue, and somaticsymptoms [18]. All research practices were conductedunder the approval of the Vietnamese government and theDa Nang Department of Health.

2.2. Variables

This study represents one component of a larger multi-component needs assessment survey. Participants engaged ina structured interview that, in addition to collecting SRQ-20data, assessed demographic information.

Demographics included age, gender, marital status, ethnicgroup, religious affiliation, employment status, and education.

The SRQ-20 is a 20 item self-report measure of mentalhealth that can be administered via interview or via paper/pencil questionnaire [20]. Item responses are recorded asbinary (yes=1, no=0) and covered a 30 day recall period.Summing items gives a maximum total score of 20.Individual items are constructed to tap general aspects ofnon-psychotic mental distress, and are intended to berepresentative of several mental health constructs. Resultsare recommended to be reported as a dichotomous “case” or“non-case.” However, this general “caseness" classificationis based on the total composite score of the individual items,and may aggregate over potentially distinct types of mentaldisorders. Based on the recommendations of the literature[21,26], a cut-off of 7/8 (i.e., 7=probable non-case; 8=probable case) has been commonly reported in a range ofstudies conducted in developing countries and is recom-mended by the WHO [20,26]. The SRQ-20 has been found

to be a reliable and valid screening instrument in Vietnamesestudies [14,21], and high internal reliability was found in thepresent sample (Cronbach's α= .87).

2.3. Statistical analyses

A latent variable modeling approach using the commonfactor model (CFM) was chosen to investigate theunderlying dimensional structure of the SRQ-20. Previouspsychometric studies on the SRQ-20 have primarily reliedupon principal components analyses (PCAs) [23–25]. WhilePCA can provide results that are consistent with the commonfactor model, there are strong theoretical reasons to preferCFM to PCA. PCA is a data reduction technique that extractscomponents based on the total observed variable (co)variances. In contrast, the common factor model decomposesthe observed variable (co)variation into that which iscommon across the items (i.e., the common factors) andthat which is unique to each item. This unique/specificcomponent also contains random error. Principal compo-nents are calculated without explicitly taking into accountrandom error, which is present in self-report data. Thus,interpretation regarding the purported theoretical constructsbeing measured by the instrument can be more difficult [27].Furthermore, since unique item variance is also included inthe principal components, it is possible that estimates of theextracted factors and their loadings can be distorted [28]. Asnoted, factor analysis is concerned with partitioning the co-variance among a set of observed variables into commonvariance and item unique variance plus random error,thereby providing a more theoretically grounded approachfor investigating latent structures. In the evaluation of theitems of an assessment instrument, an accurate understand-ing of the latent constructs lends support for the structuralvalidity and theoretical basis for the scale. Factor analysishas been recommended for the development and refinementof clinical assessment instruments and for use in socialsciences [27–29].

Three confirmatory factor analysis (CFA) models were fitto the data. First, a CFA of a single-factor structure wasconducted, since this is the model that is assumed to hold ifthe 20 items are summed to form a single mental healthcomposite variable. This model is consistent with the scale'scommon use as a single-factor measurement of mentaldistress in clinical and research settings. However, previousanalyses of the psychometric properties of the SRQ-20 havesupported various multidimensional models [22–25]; thus,we proposed to explore potential factor structures of the scalein the present sample. Exploratory factor analysis (EFA) wascarried out to examine the dimensionality of the SRQ-20items. Based on the examination of the scree plot and theproportionality of the Eigen values, a two-factor exploratorysolution and a three-factor exploratory solution wereobtained. Oblique Geomin rotation was used to facilitatethe interpretation of the two and three factor loading patterns.Based on the EFA findings, we then tested the fit of the two-

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factor and three-factor solutions by conducting additionalCFAs. Standard cut-offs of acceptability for several fitindexes were used to evaluate overall fit of the CFA models.These include the root mean squared error of approximation(RMSEA) of 0.10 as marginal fit, 0.08 as acceptable fit, and0.05 or below as good fit, as well as Tucker–Lewis index(TLI) and comparative fit index (CFI) of 0.95 or higher [30].

All model fitting was done using the Mplus version 6.1software [31]. The common factor modeling approachproduces a tetrachoric item association that is estimatedpairwise from all available data. All models were fit to theraw data using the weighted least squares mean and variance(WLSMV) adjusted estimator with robust standard errors.This approach has been shown to have good statisticalproperties for estimation with binary variables [32,33].

3. Results

3.1. Demographic characteristics

Demographic characteristics of the sample are summa-rized in Table 1. The sample was composed of slightly more

Table 1Demographic characteristics of survey of Vietnamese adults (N=4980).

% N

GenderFemale 53.9 2685Male 46.1 2295Ethnic GroupKinh 94.0 4681Rac Lay 4.3 215Other 1.7 84Marital StatusMarried 70.6 3517Single 18.9 942Divorced 1.1 56Separated 0.7 35Widowed 8.6 428Religious AffiliationNone 68.5 3413Buddhist 21.3 1062Christian 8.8 439Other 1.3 64Employment StatusEmployed 57.3 2850Retired/Elderly 9.6 477Employed in Home 9.1 453Student 3.5 175Cannot Work 4.5 222Unemployed 2.7 136Other 13.4 667EducationNo Schooling 7.3 364Uncompleted Primary 18.2 908Completed Primary 27.7 1380Completed Secondary 22.2 1108Completed High School 15.0 747Completed Vocation 2.7 134Completed College/University/Postgraduate 6.1 302

women than men (53.9% and 46.1%, respectively). Partic-ipants were on average 41.53 years of age (SD=16.30, range18–96 years).

3.2. Analysis of the SRQ-20 single factor structure

Given that the SRQ-20 is used as a mental healthcomposite variable, we first conducted a CFA to testwhether a single factor model had an acceptable fit thataccounted for the associations between the 20 scale items.This model provided a marginal fit to these data: CFI= .924,TLI= .915, RMSEA= .065 (CI: .064–.067). This findingsuggests that a single general distress factor structure doesnot adequately fit the SRQ-20 data in this sample, and thepractice of summing the items into a single composite totalscore is not well supported by this measurement model.There is a need for further exploration of the latent variablestructure of the items.

3.3. Exploratory analysis of SRQ-20 factor structure

The data were then submitted to an exploratory factoranalysis, and the number of factors retained was determinedusing both the scree plot and the common varianceaccounted for by the factors. The EFA suggested twopotential solutions. The first structure was a correlated three-factor solution with interpretable factors which we named“Negative Affect,” “Somatic Complaints,” and “Hopeless-ness” (Table 2). The Negative Affect factor was representedby items assessing loss of pleasure in activities, feelingunhappy, and difficulty thinking clearly. The SomaticComplaints factor was characterized by items that addressedphysical symptoms, including fatigue, poor sleep, poorappetite, and feeling shaky. The Hopelessness factor hadhigh loadings on items such as feeling worthless andthoughts of suicide. The three factors were correlated asfollows: Negative Affect and Hopelessness, r= .47; NegativeAffect and Somatic Complaints, r = .72; and SomaticComplaints and Hopelessness, r= .53.

A second plausible solution derived from the EFA was abi-factor model (BFM). This model was considered due tothe presence of a dominant first Eigen value in the EFA. ABFM proposes two types of common factors: a singlegeneral factor (i.e., general distress) defined by loadings onall of the SRQ-20 items, and additional sub-domain or groupfactors defined by factor loadings on specific subsets ofitems. The BFM posits a structure for the covariation amongthe items that simultaneously includes a single dominantgeneral factor defined across all of the scale items, and morenarrowly defined group factors based on subsets of context-specific items.

3.4. Confirmatory analyses: Bi-factor model andthree-factor model

The validity of both the three-factor and the bi-factorsolutions suggested by the EFA was tested using CFA. Inevaluating these models, the number of factors and the

Table 2Oblique rotated factor loadings of the 20-item Self-Reporting Questionnairefor exploratory factor analysis.

Item descriptions Negativeaffect

Somaticcomplaints

Hopelessness

Do you have troublethinking clearly?

0.843 0.068 −0.060

Do you feel unhappy? 0.647 0.017 0.270Do you cry more than usual? 0.523 0.014 0.283Do you find it difficult to enjoy

your daily activities?0.672 0.017 0.213

Do you find it difficult tomake decisions?

0.950 −0.116 −0.007

Is your daily work suffering? 0.682 −0.015 0.145Have you lost interest in things? 0.662 −0.048 0.303Do you feel nervous tense

or worried?0.443 0.340 0.059

Are you easily frightened? 0.363 0.385 −0.014Do you often have headaches? 0.004 0.734 0.006Is your appetite poor? 0.086 0.733 −0.004Do you sleep badly? 0.070 0.684 0.029Do your hands shake? 0.082 0.455 0.123Is your digestion poor? 0.036 0.927 −0.502Do you feel tired all the time? −0.014 0.725 0.315Do you have uncomfortable

feelings in your stomach?−0.017 0.969 −0.563

Are you easily tired? −0.002 0.769 0.245Are you unable to play a useful

part in life?0.111 0.060 0.778

Do you feel that you are aworthless person?

0.223 −0.008 0.808

Has the thought of ending yourlife been in your mind?

0.320 0.145 0.417able 3omparison of the item loadings from bifactor analysis: General distressctor versus sub-group factors.

em descriptions Generalfactor

Groupfactor

o you have troublethinking clearly?

0.69 0.49

o you feel unhappy? 0.71 0.39o you cry more than usual? 0.63 0.30o you find it difficult to enjoyyour daily activities?

NegativeAffect

0.68 0.44

o you find it difficult tomake decisions?

0.63 0.60

your daily work suffering? 0.62 0.43ave you lost interest in things? 0.68 0.43o you feel nervous tenseor worried?

0.74 0.19

re you easily frightened? 0.68 0.12

o you often have headaches? 0.70 0.19your appetite poor? 0.76 0.25o you sleep badly? 0.72 0.20o your hands shake? Somatic

Complaints0.59 0.10

your digestion poor? 0.49 0.69o you feel tired all the time? 0.90 0.09o you have uncomfortable feelingsin your stomach?

0.43 0.76

re you easily tired? 0.90 0.12

re you unable to play a usefulpart in life?

0.65 0.65

o you feel that you are aworthless person?

Hopelessness 0.71 0.64

as the thought of ending yourlife been in your mind?

0.72 0.23

402 K.J. Stratton et al. / Comprehensive Psychiatry 54 (2013) 398–405

relationship between factors and observed SRQ-20 itemswere specified according to the results from the EFA. Thethree-factor CFA demonstrated acceptable fit statistics(CFI= .956, TLI= .950, RMSEA= .050 [CI: .048–.052]),suggesting that three factors were present that could bemeaningfully interpreted. This correlated three-factor modelwas a better fit to the data compared to the single-factormodel that we first evaluated using CFA.

We then fit a CFA model for the BFM structure. Thismodel provided further improvement in the overall fitstatistics: CFI = .977, TLI = .971, RMSEA= .038 (CI:.036–.040). Table 3 shows a comparison of the factorloadings for each of the SRQ-20 items on the general factorand the specific group factors, as defined by the BFM.

3.5. Analysis of sex and age effects

Finally, we investigated whether the demographiccovariates of sex and age had significant effects on thelatent variable structure. These covariates were selected onthe basis of findings from previous studies of mental healthin Vietnam suggesting that gender and age are related todifferences in SRQ-20 scores [14,16]. The sex and agecovariates were examined in the single factor model.Although our results suggest that a multidimensional factorstructure may be plausible, and indeed, provide a more valid

measurement model for the latent mental health constructsassessed by the SRQ-20 in this sample, the single-factorstructure remains the predominant model in both clinical andresearch applications. Thus, we decided to investigate thedemographic covariates in this single-factor structure inorder to increase generalizability and better situate thefindings within the extant literature on the SRQ-20 inVietnamese adults.

A significant effect was found for sex, indicating thatfemales have a higher mean on the factor compared tomales. Notably, this model produced a relatively poorer fitcompared to the model that did not include the covariates(CFI= .911, TLI= .902, RMSEA= .061 [CI: .059–.062]),suggesting that the scale may not be functioning equiva-lently for men and women. This possibility was furtherexamined by testing a male–female measurement invari-ance model. Testing for invariance involves two multiplegroup models. The first is a saturated model that allowsfactor loadings and thresholds to be freely estimated in themale and female groups. In a second restricted model,factor loadings and thresholds for all items are forced to bethe same across the groups. This test was highly significantbased on the robust chi-square test (χ2 =210, df=18,pb .001), indicating that at least some of the SRQ-20 itemsare differentially functioning in males and females, and that

TCfa

It

D

DDD

D

IsHD

A

DIsDD

IsDD

A

A

D

H

403K.J. Stratton et al. / Comprehensive Psychiatry 54 (2013) 398–405

individual differences on the factor may not be equivalentfor males and females. Further testing indicated that theprimary source of misfit was due to threshold differencesrather than factor loading differences. Thus, there isevidence that men and women are differentially endorsingsome items, and that these differences in reporting may beimpacting how individual differences are related to thegeneral factor underlying the mental health construct beingmeasured by the SRQ-20 items in this sample.

4. Discussion

This report provides the first analysis of the SRQ-20factor structure in a large epidemiological survey ofVietnamese adults. Previous validity and reliability studieshave established the SRQ-20 as a screening instrument inVietnam by determining the appropriate cut-off scores[14,21]. This study expanded on previous work byevaluating the relationship between the individual itemsand the latent mental health constructs they measure, therebyproviding a more thorough understanding of how the SRQ-20 items relate to one another when administered to acommunity sample of Vietnamese adults.

Results from the study suggest two plausible models forthe SRQ-20 factor structure that showed improvements inmodel fit over the single-factor structure of the items, whichis the predominate model assumed in the literature for thismeasure. A CFA of the 20-item scale showed a good fit to athree-factor model. The fit of the BFM further improvedoverall model-data fit. Using the BFM to compare theloading of each item on a general distress factor versussubdomain specific factors (Negative Affect, SomaticComplaints, or Hopelessness), we found the loadings forthe item-general factor to be higher, on average, than that ofthe loadings for the item-subdomain factors. Consistent withthe initial development goal of the scale, the total SRQ-20score is a reasonable and parsimonious choice for clinicalscreening and assessment. Based on the presence of a largedominant general factor, all 20 items can be treated asreflecting a common underlying concept of general, non-psychotic mental distress. However, in circumstances wherethe assessor may want to examine more specific symptomclusters that differentiate negative affect, somatic, andhopelessness constructs, this is supported by better modelfit data for the correlated three-factor model and BFM. Thisapplication of the SRQ-20 may allow for more nuancedscreening of specific mental health subtypes, therebypromoting targeted interventions for certain types of mentalhealth presentations. For example, an individual who scoredhighly on the Hopelessness symptoms may be more closelyevaluated for suicidality, whereas an individual whoendorsed many Somatic Complaints may benefit frominterventions that assist with general anxiety concerns, orhe or she may be referred for differential diagnosticassessment of physical health problems. Further research

with the SRQ-20 and established indices of psychopathologymay provide construct validity for these subdomain factorsas indicators of specific diagnostic categories.

The correlated three factor solution identified in this studyis a representation of the data that depart the most fromprevious analyses of the SRQ-20 factor structure. Given thatVietnamese health practices have been widely influenced byChinese traditional medicine practices and beliefs [34], aswell as similarities in idioms of distress in many SoutheastAsian countries [35], it seemed plausible that these resultswould yield analogous factors as in a previous study of theSRQ-20 in a community sample of Chinese adults [23].Chen and colleagues' model included a similar depressionfactor, but the anxiety and somatic items were dividedbetween two factors, which the authors named Anxiety I andAnxiety II. The Chen et al. study did not use a CFA to test thefit of this measurement model, and thus it is unknownwhether a single general distress factor may have accountedfor some of the symptom overlap. The present studyidentified depressive symptoms as a meaningful andsignificant expression of distress, as two depression-relatedfactors emerged that were distinct from somatic complaints.Other cross-cultural studies with the SRQ-20 have reported arange of three to eight extracted factors [22,24,25,36]. Due tolack of consistency in the factor structures across studies, it isunclear whether SRQ-20 factors can be reliably interpretedas sub-scales, and this represents an area for futureinvestigation. Differences in the findings may be affectedby the setting in which a study takes place, depending onwhether it is a primary care setting or a community survey.Further, the various factor structures may be impacted bycultural differences and local idioms of distress, and futurework should be directed at exploring the relationshipbetween the SRQ-20 and culturally-relevant screening andassessment tools.

The BFM, which provided the best overall fit to thesedata, specifies a single, robust general distress factorindicated by all 20 items that is consistent with thebiophysiological manifestation of mental distress that iscommon in many Southeast Asian countries, such as in thesyndrome of neurasthenia [35]. The SRQ-20 was designed asa cross-cultural screening tool, and while it may notadequately capture specific local idioms of distress, itappears sufficient for determining probable mental healthcaseness [14,16]. While there is evidence from previousstudies in Vietnam that the inclusion of a culturallyindigenous mental health screening tool can increaseidentification of cases of psychiatric disability in somecontexts [5], translated Western measures of mental healthhave been shown to be approximately equivalent in theircapacity to measure mental health constructs in somepopulations [19,34]. The SRQ-20 also has the benefit ofbeing a brief and easily administered measure that has beenimplemented in a number of community and clinical settingsworldwide, in addition to demonstrating acceptable reliabil-ity when taught to both lay interviewers and physicians in

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Vietnam [37]. The utility of an easily trainable assessmentinstrument that may be used in a variety of settings isparticularly salient when considering the limited mentalhealth resources available in Vietnam.

Another relevant finding from this study was thatmeasurement invariance tests for sex differences in factorloadings and thresholds suggested that men and women maybe differentially reporting some mental health symptoms.Sources of these differences were traced to varyingendorsement rates. Differences in male–female endorsementrates on the SRQ-20 have been similarly demonstrated inAfghanistan [38] and United Arab Emirates [39], suggestingthat gender-specific cut-off scores may be warranted and ofimportant clinical utility. Due to gaps in the existingliterature on mental health in Vietnam, it is unknownwhether the differences in this sample are indicative ofspecific cultural or societal expectations, or whether men andwomen may be distinctively sensitive to certain types ofpsychiatric problems. This is an important question to beexplored in future work.

This study is limited in that the SRQ-20 does not providespecific diagnostic information, and the factor structure wasnot compared to established measures of psychopathology,such as assessment tools for depression and anxietydisorders. Future work will explore the relationship betweenSRQ-20 items and both indigenous and Western conceptu-alizations of mental distress. In addition, the SRQ-20includes a number of items addressing somatic complaintsthat formed a distinct factor in this study, and these itemsmay measure both the presence of psychiatric symptoms aswell as concerns about physical health symptoms. Reportingof somatic concerns may be inflated in populations withchronically poor physical health, as may be the case indeveloping nations with limited health care resources.Conversely, items assessing emotional or cognitive com-plaints may be underreported due to social stigma associatedwith the reporting of mental illness or by a cultural tendencyto underreport symptoms, particularly emotional or mentaldifficulties [5,14]. Finally, the conclusions regarding ex-pressions of mental distress in this sample are limited by thecontent of the instrument. The SRQ-20 includes a limitednumber of items related to externalizing pathology, whichneglects many significant problems that individuals mayexperience. It is important to note that the SRQ-20 is a toolfor general screening of non-psychotic mental distress, anddoes not capture a full range of psychiatric concerns.

In summary, the present study provides further supportfor the SRQ-20 as a valid, reliable, and adaptable measure ofmental distress among Vietnamese adults. Results offer astructural framework for understanding how the SRQ-20items relate to one another, and may be used to detectspecific mental health constructs related to depressive affect(Negative Affect) and cognitions (Hopelessness), as well assomatic complaints. Further, the results suggest that theSRQ-20 has differential ability to discriminate cases ofmental distress among men and women. The results provide

a model-based framework for understanding the uniquemanifestations of mental distress in this sample andcontribute to knowledge of mental health needs in Vietnam.A comprehensive and culturally-sensitive understanding ofmental distress is critically important for assessment,treatment, and mental health policy considerations.

Acknowledgment

This research was supported by a grant from AtlanticPhilanthropies to the Community Health Centers of Da Nangand Khanh Hoa, Vietnam, with personnel and technicalsupport from the Veterans for America Foundation. Specialthanks to Anne Seymour for her assistance in coordinatinginternational efforts of the research team.

References

[1] World Health Organization. Mental health atlas 2011. Geneva,Switzerland: World Health Organization; 2011.

[2] Centers for Disease Control and Prevention. The role of public healthin mental health promotion. Morb Mortal Wkly Rep 2005;54(34):841-2.

[3] Demyttenaere K, Bruffaerts R, Posada-Villa J, Gasquet I, Kovess V,Lepine JP, et al. WHO World Mental Health Survey Consortium.Prevalence, severity, and unmet need for treatment of mental disordersin the World Health Organization World Mental Health Surveys. JAmer Med Assoc 2004;291(21):2581-90.

[4] Shen YC, Zhang MY, Huang YQ, He YL, Liu ZR, Cheng H, et al.Twelve-month prevalence, severity, and unmet need for treatment ofmental disorders in metropolitan China. Psychol Med 2006;36:257-67.

[5] Steel Z, Silove D, Giao NM, Phan TT, Chey T, Whelan A, et al.International and indigenous diagnoses of mental disorder amongVietnamese living in Vietnam and Australia. Br J Psychiatr 2009;194:326-33.

[6] World Health Organization. The World Health Report 2001: mentalhealth: new understanding, new hope. Geneva, Switzerland: WorldHealth Organization; 2001.

[7] Kessler RC, Angermeyer M, Anthony JC, De Graaf R, DemyttenaereK, Gasquet I, et al. Lifetime prevalence and age-of-onset distributionsof mental disorders in the World Health Organization's World MentalHealth Survey Initiative. World Psychiatr 2007;6(3):168-76.

[8] Bijl RV, de Graaf R, Hiripi E, Kessler RC, Kohn R, Offord DR, et al.The prevalence of treated and untreated mental disorders in fivecountries. Health Aff 2003;22(3):122-33.

[9] Ormel J, VonKorff M, Ustun TB, S Pini, Korten A, Oldehinkel T.Common mental disorders and disability across cultures. Results fromthe WHO Collaborative Study on Psychological Problems in GeneralHealth Care. J Am Med Assoc 1994;272(22):1741-8.

[10] Murray CJ, Lopez AD. Evidence-based health policy—lessons fromthe Global Burden of Disease Study. Science 1996;274(5288):740-3.

[11] Saraceno B, van Ommeren M, Batniji R, Cohen A, Gureje O, MahoneyJ, et al. Barriers to improvement of mental health services in low-income and middle-income countries. Lancet 2007;370(9593):1164-74.

[12] Niemi M, Thanh HT, Tuan T, Falkenberg T. Mental health priorities inVietnam: a mixed-methods analysis. BMC Health Serv Res 2010;10(cited 13 Aug 2012) Available from: http://www.biomedcentral.com/1472-6963/10/257.

[13] Nguyen NL, Hunt DD, Scott CS. Screening for depression in a primarycare setting in Vietnam. J Nerv Ment Dis 2005;193(2):144-7.

[14] Giang KB, Allebeck P, Kullgren G, Nguyen VT. The Vietnameseversion of the Self Reporting Questionnaire 20 (SRQ20) in detecting

405K.J. Stratton et al. / Comprehensive Psychiatry 54 (2013) 398–405

mental disorders in rural Vietnam: a validation study. Int J SocPsychiatr 2006;52:175-84.

[15] Tran Thi Thanh H, Tran TN, Jiang GX, Leenaars A, Wasserman D.Life time suicidal thoughts in an urban community in Hanoi, Vietnam.BMC Public Health 2006;6:76 (cited 13 Aug 2012) Available from:http://www.biomedcentral.com/1471-2458/6/76.

[16] Richardson LK, Amstadter AB, Kilpatrick DG, GabouryMT, Tran TL,Trung LT, et al. Estimating mental distress in Vietnam: use of theSRQ-20. Int J Soc Psychiatr 2010;56(2):133-42.

[17] Amstadter AB, Acierno R, Richardson LK, Kilpatrick DG, Gros DF,Gaboury MT, et al. Posttyphoon prevalence of posttraumatic stressdisorder, major depressive disorder, panic disorder, and generalizedanxiety disorder in a Vietnamese sample. J Trauma Stress 2009;22(3):180-8.

[18] Acierno R, Amstadter AB, Gros DF, Richardson L, Kilpatrick DG,Trung LT, et al. A pre-/post-disaster epidemiological study of mentalhealth functioning in Vietnam's Da Nang province following typhoonXangsane. Int Perspec Vict 2009;4(1):78-85.

[19] Steel Z, Silove D, Chey T, Bauman A, Phan T, Phan T. Mentaldisorders, disability and health service use amongst Vietnameserefugees and the host Australian population. Acta Psychiatr Scand2005;111(4):300-9.

[20] World Health Organization. A user's guide to the Self ReportingQuestionnaire (SRQ). Geneva, Switzerland: World Health Organiza-tion; 1994.

[21] Tuan T, Harpham T, Huong N. Validity and reliability of the Self-Reporting Questionnaire 20 items (SRQ20) in Vietnam. Hong Kong JPsychiatr 2004;14:15-8.

[22] Scholte WF, Verduin F, van Lammeren A, Rutayisire T, Kamper-man AM. Psychometric properties and longitudinal validation ofthe Self-Reporting Questionnaire (SRQ-20) in a Rwandan commu-nity setting: a validation study. BMC Med Res Methodol2011;11(116) (cited 13 Aug 2012) Available from: http://www.biomedcentral.com/1471-2288/11/116.

[23] Chen S, Zhao G, Li L, Wang Y, Chiu H, Caine E. Psychometricproperties of the Chinese version of the Self-Reporting Questionnaire20 (SRQ-20) in community settings. Int J Soc Psychiatr 2009;55(6):538-47.

[24] Iacoponi E, Mari JJ. Reliability and factor structure of the Portugueseversion of Self-Reporting Questionnaire. Int J Soc Psychiatr 1989;35(3):213-22.

[25] Sen B. An analysis of the nature of depressive phenomena in primaryhealth care utilising multivariate statistical techniques. Acta PsychiatrScand 1987;76(1):28-32.

[26] Harpham T, Reichenbaum M, Oser R, Thomus E, Hamid N, Jaswal S,et al. How to do (or not to do…). Measuring mental health in a costeffective manner. Health Policy Plan 2004;18:344-9.

[27] Floyd FJ, Widaman KF. Factor analysis in the development andrefinement of clinical assessment instruments. Psychol Assess 1995;7(3):286-99.

[28] Costello AB, Osborne JW. Best practices in exploratory factoranalysis: four recommendations for getting the most from youranalysis. Pract Assess Res Eval 2005;10(7) (cited 13 Aug 2012)Available from: http://pareonline.net/getvn.asp?v=10&n=7.

[29] Gorsuch RL. Exploratory factor analysis: its role in item analysis.J Personal Assess 1997;68(3):532-60.

[30] Hu LT, Bentler PM. Cutoff criteria for fit indices in covariancestructure analysis: conventional criteria versus new alternatives. StructEqu Model 1999;6:1-55.

[31] Muthén LK, Muthén BO. Mplus User's Guide. 6th ed. Los Angeles,CA: Muthén & Muthén; 1998-2010.

[32] Wirth RJ, Edwards MC. Item factor analysis: current approaches andfuture directions. Psychol Methods 2007;12:58-79.

[33] Flora DB, Curran PJ. An empirical evaluation of alternative methods ofestimation for confirmatory factor analysis with ordinal data. PsycholMethods 2004;9:466-91.

[34] Phan T, Steel Z, Silove D. An ethnographically derived measure ofanxiety, depression and somatization: the Phan Vietnamese PsychiatricScale. Transcult Psychiatr 2004;41(2):200-32.

[35] Chung RC, Singer MK. Interpretation of symptom presentation anddistress. A Southeast Asian refugee example. J Nerv Ment Dis 1995;183(10):639-735.

[36] Tafari S, Aboud FE, Larson CP. Determinants of mental illness in arural Ethiopian adult population. Soc Sci Med 1991;32(2):197-201.

[37] Amstadter AB, Richardson L, Acierno R, Kilpatrick DG, GabouryMT, Tran T, et al. Does interviewer status matter? An examination oflay interviewers and medical doctor interviewers in an epidemiologicalstudy in Vietnam. Int Perspect Vict 2010;5(1):55-62.

[38] Ventevogel P, De Vries G, Scholte WF, Shinwari NR, Faiz H, NasseryR, et al. Properties of the Hopkins Symptom Checklist-25 (HSCL-25)and the Self-Reporting Questionnaire (SRQ-20) as screening in-struments used in primary care in Afghanistan. Soc PsychiatryPsychiatr Epidemiol 2007;42(4):328-35.

[39] Ghubash R, Daradkeh T, El-Rufaie OF, Abou-Saleh MT. Acomparison of the validity of two psychiatric screening questionnaires:the Arabic General Health Questionnaire (AGHQ) and Self-ReportingQuestionnaire (SRQ-20) in UAE, using Receiver Operating Charac-teristic (ROC) analysis. Eur Psychiatry 2001;16(2):122-6.