Assessment and characterization of phenotypic heterogeneity of anxiety disorders across five large cohorts

To achieve sample sizes necessary for effectively conducting genome‐wide association studies (GWASs), researchers often combine data from samples possessing multiple potential sources of heterogeneity. This is particularly relevant for psychiatric disorders, where symptom self‐report, differing assessment instruments, and diagnostic comorbidity complicates the phenotypes and contribute to difficulties with detecting and replicating genetic association signals. We investigated sources of heterogeneity of anxiety disorders (ADs) across five large cohorts used in a GWAS meta‐analysis project using a dimensional structural modeling approach including confirmatory factor analyses (CFAs) and measurement invariance (MI) testing. CFA indicated a single‐factor model provided the best fit in each sample with the same pattern of factor loadings. MI testing indicated degrees of failure of metric and scalar invariance which depended on the inclusion of the effects of sex and age in the model. This is the first study to examine the phenotypic structure of psychiatric disorder phenotypes simultaneously across multiple, large cohorts used for GWAS. The analyses provide evidence for higher order invariance but possible break‐down at more detailed levels that can be subtly influenced by included covariates, suggesting caution when combining such data. These methods have significance for large‐scale collaborative studies that draw on multiple, potentially heterogeneous datasets. Copyright © 2016 John Wiley & Sons, Ltd.     

Refining and validating the Social Interaction Anxiety Scale and the Social Phobia Scale

Background: The Social Interaction Anxiety Scale and Social Phobia Scale 6 are companion measures for assessing symptoms of social anxiety and social phobia. The scales have good reliability and validity across several samples, 3 , 6 however, exploratory and confirmatory factor analyses have yielded solutions comprising substantially different item content and factor structures. These discrepancies are likely the result of analyzing items from each scale separately or simultaneously. The current investigation sets out to assess items from those scales, both simultaneously and separately, using exploratory and confirmatory factor analyses in an effort to resolve the factor structure. Methods: Participants consisted of a clinical sample (n5353; 54% women) and an undergraduate sample (n5317; 75% women) who completed the Social Interaction Anxiety Scale and Social Phobia Scale, along with additional fear‐related measures to assess convergent and discriminant validity. Results: A three‐factor solution with a reduced set of items was found to be most stable, irrespective of whether the items from each scale are assessed together or separately. Items from the Social Interaction Anxiety Scale represented one factor, whereas items from the Social Phobia Scale represented two other factors. Conclusion: Initial support for scale and factor validity, along with implications and recommendations for future research, is provided. Depression and Anxiety, 2009. © 2009 Wiley‐Liss, Inc.     

Cross‐cultural factorial validation of the Clinical Interview Schedule – Revised (CIS‐R); findings from a nationally representative survey (EMPIRIC)

The Clinical Interview Schedule – Revised (CIS‐R) has been widely adopted across cultures to assess common mental disorders. We assessed the factorial validity of the CIS‐R across ethnic minority groups, using data from a nationally representative survey conducted in England in 2000. The sample comprised White British (n = 837), Irish (n = 733), Black Caribbean (n = 694), Bangladeshi (n = 650), Indian (n = 643) and Pakistani (n = 724) respondents. Ordered logistic regression determined the reporting of CIS‐R symptoms. Principal components analysis (PCA) determined the underlying construct of the CIS‐R in White British participants. These factor solutions were then assessed for “best fit” using confirmatory factor analyses (CFAs) across all ethnic groups. In ordered logistic regression analyses, there was heterogeneity in the reporting of worries, phobias, panic and somatic symptoms across ethnic minority groups relative to the White British group. “Best” fit solutions confirmed through CFA were models where all symptoms were allowed to vary across ethnic groups, or models where an underlying “depression‐anxiety” construct was held invariant while “somatic symptoms” were permitted to vary across groups, although differences between models assessed were slight. In conclusion, there may be benefits in assessing the functioning of certain CIS‐R items within specific cultural contexts to ensure adequate face validity of the CIS‐R. Copyright © 2014 John Wiley & Sons, Ltd.     

Psychometric properties of the Strength and Difficulties Questionnaire from five European countries

The Strength and Difficulties Questionnaire (SDQ) is a brief screening instrument for assessing emotional and behavioural problems in children and adolescents. This study examined the factor structure and validity of the self‐report original English version of the SDQ and four of its many translations (German, Cypriot Greek, Swedish, and Italian). A total of 2418 adolescents from five European countries (Germany, Cyprus, England, Sweden, Italy), ages 12 to 17 years, participated. The sample was drawn from general (school) populations. In addition to the SDQ, all participants completed the Spence Children's Anxiety Scale (SCAS), a measure of anxiety symptoms. The internal consistency and validity of the SDQ total difficulties were good for most countries. Confirmatory factor analysis showed that both five‐ and three‐factor models provided good fit for the whole sample; however, the three‐factor model fit somewhat better than the five‐factor model. The factor structure differed across countries, with the three‐factor model showing better fit indices in Cyprus, whereas the five‐factor model fitted better in Germany. Fit indices for the UK, Sweden, and Italy were poor for both models. When the reversed items were removed, the goodness‐of‐fit improved significantly for the total sample and in each country. It is therefore recommended that the reversed items be removed or re‐worded in future studies. Copyright © 2012 John Wiley & Sons, Ltd.     

The Reynolds Adolescent Depression Scale in New Zealand adolescents

OBJECTIVE: To examine aspects of the reliability and validity of the Reynolds Adolescent Depression Scale (RADS) in measuring depression in New Zealand adolescents of all major ethnic groups. METHOD: A sample of 9699 randomly selected New Zealand secondary school students participated in the Youth2000 Health and Wellbeing Survey which included the RADS. Data from this survey have been used to assess some aspects of the reliability and validity of the RADS in the New Zealand context across different ethnic groups. Cronbach's alpha, item-total score correlations, correlation to other questions and a factor analysis were done in order to examine the internal reliability, content validity, convergent validity and construct validity of the data and compare to the original Reynolds validation study. RESULTS: Tests of the scale resulted in scores over 0.90 on Cronbach's alpha and high item-total score correlations, with a median correlation of 0.62 and 25 of the 30 correlations measuring more than 0.5. The scores were found to have similar factor structure to the original scale and the correlations to other depression related questions indicate acceptable concurrent validity. CONCLUSIONS: On all of the tests conducted, the RADS was found to have acceptable reliability and validity for New Zealand adolescents across the major different ethnic groups, indicating that it is a valid and appropriate instrument to use with New Zealand adolescents.     

Attending to the Attentional Control Scale for Children: Confirming its factor structure and measurement invariance

The Attentional Control Scale for Children (ACS-C) is a widely used self-report questionnaire that measures attentional control in youth. Previous research examined factor-structure and validation of the ACS-C and yielded a 2-factor structure with Attentional Focusing and Attentional Shifting subscales. This study used a confirmatory factor analysis in a large, ethnically diverse sample of clinic-referred anxious youth (N = 442, ages 7–16 years) to compare model fit of three models, the original two-factor model of the ACS-C, a two-factor model of a modified ACS-C (two items re-assigned from Attentional Focusing to Attentional Shifting, three items removed from Attentional Focusing, and two items removed from Attentional Shifting), and a single-factor model. Results reveal best model fit for the two-factor modified ACS-C. This model had strong factorial invariance across sex, partial invariance across ethnicity, and was variant across age. Also, total and subscale scores for the two-factor modified ACS-C correlated with anxiety and depression symptom scale scores, supporting its concurrent validity. Findings confirm the two-factor structure of the modified ACS-C. Future research implications relating to attentional control in children are discussed.     

Cross‐cultural measurement invariance of the General Health Questionnaire‐12 in a German and a Colombian population sample

While the General Health Questionnaire, 12‐item version (GHQ‐12) has been widely used in cross‐cultural comparisons, rigorous tests of the measurement equivalence of different language versions are still lacking. Thus, our study aims at investigating configural, metric and scalar invariance across the German and the Spanish version of the GHQ‐12 in two population samples. The GHQ‐12 was applied in two large‐scale population‐based samples in Germany (N = 1,977) and Colombia (N = 1,500). To investigate measurement equivalence, confirmatory factor analyses were conducted in both samples. In the German sample mean GHQ‐12 total scores were higher than in the Colombian sample. A one‐factor model including response bias on the negatively worded items showed superior fit in the German and the Colombian sample; thus both versions of the GHQ‐12 showed configural invariance. Factor loadings and intercepts were not equal across both samples; thus GHQ‐12 showed no metric and scalar invariance. As both versions of the GHQ‐12 did not show measurement equivalence, it is not recommendable to compare both measures and to conclude that mental distress is higher in the German sample, although we do not know if the differences are attributable to measurement problems or represent a real difference in mental distress. The study underlines the importance of measurement equivalence in cross‐cultural comparisons.     

Psychometric evaluation of a Dutch version of the Mini PAS‐ADD for assessing psychiatric disorders in adults with different levels of intellectual disability

Background People with intellectual disabilities (ID) have an increased vulnerability to develop psychiatric problems. Moreover, the early recognition and the accurate diagnosis of psychiatric disorders in the population of persons with ID are challenging. Method A Dutch version of the Mini PAS‐ADD, which is a screening instrument for identification of mental health problems in people with ID, was evaluated in terms of internal consistency, interinformant reliability, item grouping and criterion validity based on a large‐scale random sample (n = 377) and a clinical sample (n = 99) of adults with ID. Results The Dutch version of the Mini PAS‐ADD showed moderate internal consistency, and moderate concordance among informants. Both aspects of the reliability were comparable for different levels of ID. A factor analysis largely confirmed the scale structure. Concurrent validity with the Reiss Screen for Maladaptive Behavior was high for the Depression, Psychosis and Autism scale. The outcome of the criterion‐validity analysis indicated high specificity. The sensitivity for specific psychiatric disorders by the corresponding scales was moderate, but the general sensitivity for the presence of psychopathology on the basis of any of the scales was satisfying. Conclusions The present research reconfirmed the use of the Mini PAS‐ADD as a primary screening device for the identification of mental health problems among people with ID.     

Self-disorders and the Schizophrenia Spectrum: A Study of 100 First Hospital Admissions

Introduction: Self-disorders (SD) have been described as a core feature of schizophrenia both in classical and recent psychopathological literature. However, the specificity of SD for the schizophrenia spectrum disorders has never been demonstrated in a diagnostically heterogeneous sample, nor has the concurrent validity of SD been examined. Aim: (1) To examine the specificity of Examination of Anomalous Self-Experiences (EASE) measured SD to the schizophrenia spectrum disorder in first contact inpatients, (2) to explore the internal consistency and factorial structure of the EASE, (3) to assess the concurrent validity of SD by exploring correlations between SD and the canonical psychopathological dimensions of schizophrenia, (4) to explore relations of SD to intelligence, sociodemographic, and extrinsic illness characteristics. Methods: A total of 100 consecutive first admission patients underwent a comprehensive psychopathological examination and an assessment of SD with the EASE scale. The diagnostic distribution of the EASE scores was tested with ANOVA, whereas the relations between the EASE scores and other symptomatic dimensions of schizophrenia were tested with Spearman’s rho. A potential factorial structure and the internal consistency of the EASE scale were also examined. Results: SD aggregated significantly in the schizophrenia spectrum disorders, with no differences between schizophrenia and schizotypal disorders. EASE scores correlated moderately with canonical psychopathological dimensions of schizophrenia. Factor analysis of the EASE disclosed only one factor and the internal consistency of the EASE was excellent. Conclusions: SD aggregate selectively in the schizophrenia spectrum disorders, with similar levels in schizophrenia and schizotypy. The study lends validity to the view of SD as an experiential vulnerability phenotype of the schizophrenia spectrum disorders.     

Factor structure of the Impact of Event Scale‐Revised in two different Peruvian samples

Background: This article studied the factor structure of the Impact of Event Scale‐Revised (IES‐R) in two samples in Peru, i.e., a sample of survivors of a fire (N=174) and a university student sample (N=562). Methods: First, confirmatory factor analysis was used to compare nine different models of posttraumatic stress disorder symptoms as evaluated by the IES‐R in both of the samples separately. The model with the best fit in both samples had four correlated factors, i.e., Intrusion, Avoidance, Hyperarousal and Sleep Disturbance. Second, the degree of factorial invariance of the IES‐R was compared in both the samples using multiple group confirmatory factor analysis. Results and Conclusions: The results showed almost no differences between both samples. Finally, the results supported the internal consistency, as well as the concurrent and convergent validity of the IES‐R in Peru. Depression and Anxiety, 2009. © 2009 Wiley‐Liss, Inc.     

Psychometric properties of a Persian-language version of the Beck Depression Inventory--Second edition: BDI-II-PERSIAN

The Beck Depression Inventory (BDI) is perhaps the most commonly used screening instrument for depression in the general population. We examined the psychometric properties of a Persian-language version of the second edition of this instrument (BDI-II) [Beck et al., 1996] in an Iranian college-student sample. In a sample of 125 student volunteers from two Iranian universities, we compared mean item scores on the BDI-II-Persian with those on the English-language version administered to North American college students, and assessed internal consistency and test-retest reliability of the BDI-II-Persian and its concurrent validity against a measure of negative automatic thoughts in depression, the Automatic Thoughts Questionnaire [Hollon and Kendall, 1980]. We also examined the factor structure of the BDI-II-Persian through comparing the fit of various proposed models to the data using confirmatory factor analysis. The BDI-II-Persian had high internal consistency (Cronbach's alpha=0.87) and acceptable test-retest reliability (r=0.74). The instrument correlated strongly with the Automatic Thoughts Questionnaire. In factor analysis, models with strongly correlated affective-cognitive and somatic-vegetative factors provided a better fit than models with one global factor. These data support the reliability and concurrent validity of the BDI-II-Persian as a measure of depressive symptoms in nonclinical samples.     

A new look at the construct validity of the K6 using Rasch analysis

The Kessler six‐item psychological distress (K6) scale is widely used to screen for mental disorders; however, information is lacking on the rating scale performance or dimensionality structure of the scale. This study used a population based sample (n = 7596) to evaluate the construct validity of the K6 scale using Rasch partial credit analysis. The analysis showed that almost all of the five‐point rating scales in the K6 items were used appropriately to differentiate psychological distress of the study participants. The analysis provided evidence of unidimensionality of the scale, although items 1 (so sad) and 3 (restless or fidgety) might offer a potential second off‐dimensional component. All items appeared to fit the Rasch model's expectation as demonstrated by the acceptable item fit statistics. The study participants demonstrated valid response patterns when answering K6 items, except for some who were younger or had higher psychological distress. This study using Rasch analysis confirms the construct validity of the K6 scale and suggests that the K6 is a useful and valid instrument for assessing psychological distress in the mid‐aged general population. Further research can facilitate better understanding about the unidimensionality of the scale. Copyright © 2014 John Wiley & Sons, Ltd.     

Validity and reliability of the Caregiver Reaction Assessment scale among primary informal caregivers for older persons in Singapore

Previous studies evaluating the validity and reliability of the Caregiver Reaction Assessment (CRA) scale (24 items; five subscales: schedule, health, finances, family support, and esteem) in different countries are not fully congruent. This article assesses the validity and reliability of the CRA among informal caregivers of older persons in Singapore. Data from a national survey of 1190 primary informal caregivers of Singaporeans aged ≥75 years with ≥1 activity of daily living limitation was analyzed. Fit of the five-factor model was tested in half of the sample using confirmatory factor analysis (CFA) and the other half subjected to exploratory factor analysis (EFA). The CRA was modified accordingly and again subjected to CFA. The CRA's measurement equivalence/invariance (ME/I) across language of administration (Chinese/English/Malay) was assessed. CFA showed a poor fit for the five-factor model. EFA suggested the presence of four factors, three items to have neither sufficient nor unique factor loadings and items on two of the subscales to load on a single factor. CFA of the ‘modified’ CRA (21 items; four subscales: schedule and health, finances, family support, and esteem) suggested a better fit for the four-factor model than for the five-factor model. ME/I analysis supported partial invariance of the CRA across language of administration. The CRA scale should be assessed for relevance in Asian settings. With the suggested modifications, it is suitable for assessing negative and positive effects of caregiving among informal caregivers of older persons with activity limitations in Singapore.     

Stomaching uncertainty: Relationships among intolerance of uncertainty,eating disorder pathology,and comorbid emotional symptoms

Intolerance of uncertainty (IU) is proposed to be a transdiagnostic vulnerability factor for various emotional disorders. There is robust evidence for the role of IU in anxiety and depressive disorders, but a paucity of evidence in eating disorders (ED). This study evaluated the factorial validity, internal consistency, and convergent validity of the Intolerance of Uncertainty Scale—Short Form (IUS-12; Carleton, Norton, & Asmundson, 2007), and examined whether IU is associated with ED pathology and comorbid emotional symptoms, in a clinical sample with EDs (N = 134). A unitary factor solution provided the best fit. The IUS-12 showed excellent internal consistency, and good convergent validity. IU had an indirect effect on dietary restraint, purging, and emotional symptoms via overvaluation of eating, weight, and shape. The indirect effect was not significant for bingeing. Findings provide partial support for the notion that IU is a vulnerability factor for ED pathology and support the notion that IU is a transdiagnostic vulnerability factor for emotional symptoms. Limitations, research implications, and future directions for research are discussed.     

The structure of the Montgomery–Åsberg depression rating scale over the course of treatment for depression

The Montgomery–Åsberg Depression Rating Scale (MADRS) is a widely used clinician‐rated measure of depressive severity. Empirical support for the factor structure of the MADRS is mixed; further, the comparison of MADRS scores within and between patients requires the demonstration of consistent instrument properties. The objective of the current investigation was to evaluate MADRS factor structure as well as MADRS factorial invariance across time and gender. The MADRS was administered to 821 depressed outpatients participating in a large‐scale effectiveness study of combined pharmacotherapy and psychotherapy for depression. Treatment outcome did not differ across treatment groups. Factor structure and invariance was evaluated via confirmatory factor analysis. A four‐factor model consisting of Sadness, Negative Thoughts, Detachment and Neurovegetative symptoms demonstrated a good fit to the data. This four‐factor structure was invariant across time and gender. A hierarchical model, in which these four factors served as indicators of a general depression factor, was also supported. A limitation of the current study is the lack of comprehensive characterization of patient clinical features; results need to be replicated in more severely depressed or treatment refractory patients. Overall, evidence supported the use of the MADRS total score as well as subscales focused on affective, cognitive, social and somatic aspects of depression in male and female outpatients. Copyright © 2013 John Wiley & Sons, Ltd.     

Technology and everyday functioning in people with intellectual disabilities: a Rasch analysis of the Everyday Technology Use Questionnaire (ETUQ)

Background As people with intellectual disabilities (ID) today live integrated in society and use different technological artefacts and services in their everyday life, more in‐depth evaluation methods are crucial to detect strengths and limitations of their everyday technology use. The Everyday Technology Use Questionnaire (ETUQ) was originally designed to investigate the extent to which older adults with cognitive limitations can use the everyday technology that is of relevance to them. The purpose of this study was to explore and evaluate evidence of the validity of ETUQ among adult persons with ID. Methods The original 93‐item ETUQ was used to interview 120 adult participants with ID, recruited from a region in northern Sweden. A Rasch model was used to analyse the psychometric properties of the rating scale, scale validity, person response validity and person separation. Results The ETUQ rating scale displayed sound psychometric properties when used with this sample. The goodness‐of‐fit statistics showed that 15 (16%) of the 93 items demonstrated higher values than expected. A step‐by‐step removal process of items not demonstrating fit to the model resulted in an ETUQ version with 46 items (49%) that met all the criteria for scale validity. Fifteen participants (12%), primarily with mild ID, still demonstrated a higher number of unexpected responses included in ETUQ. Conclusions The results of this study indicate that the ETUQ generates a valid measure of perceived difficulty in using everyday technology including adult persons with ID.     

Confirmatory factor analysis of the wechsler memory scale-revised in a mixed clinical population

Abstract

Previous exploratory factor analyses (EFA) of the Wechsler Memory Scale-Revised (WMS-R) have yielded highly disparate factor structures, while the few reported confirmatory factor analyses (CFA) of this instrument have been more consistent. The present study employed a CFA approach to identify the factor structure of the WMS-R in a mixed clinical sample of 306 patients, the majority of whom had sustained mild, diffuse brain injury. Consistent with previous CFA studies, the present study found that a three-factor solution (attention/concentration, immediate memory, delayed recall) fit the data significantly better than competing models. The validity of separate verbal and visual memory indices was not supported, perhaps because of the heterogeneity of the sample.     

A large-scale validation study of the Medication Adherence Rating Scale (MARS)

Adherence to medication is an important predictor of illness course and outcome in psychosis. The Medication Adherence Rating Scale (MARS) is a ten-item self-report measure of medication adherence in psychosis [Thompson, K., Kulkarni, J., Sergejew, A.A., 2000. Reliability and validity of a new Medication Adherence Rating Scale (MARS) for the psychoses. Schizophrenia Research. 42. 241–247]. Although initial results suggested that the scale has good reliability and validity, the development sample was small. The current study aimed to establish the psychometric properties of the MARS in a sample over four times larger. The scale was administered to 277 individuals with psychosis, along with measures of insight and psychopathology. Medication adherence was independently rated by each individual's keyworker. Results showed the internal consistency of the MARS to be lower than in the original sample, though adequate. MARS total score correlated weakly with keyworker-rated adherence, hence concurrent validity of the scale appeared only moderate to weak. The three factor structure of the MARS was replicated. Examination of the factor scores suggested that the factor 1 total score, which corresponds to the Medication Adherence Questionnaire [Morisky,D.E., Green,L.W. and Levine,D.M., 1986. Concurrent and predictive validity of a self-reported measure of medication adherence. Medical Care. 24, 67–74] may be a preferable measure of medication adherence behaviour to the total scale score.     

Factor structure of the Liebowitz Social Anxiety Scale in community‐dwelling subjects in Japan

This study examined the internal consistency and structural/construct validity of the Liebowitz Social Anxiety Scale (LSAS) for community‐dwelling subjects in Japan. A cross‐sectional study that included 929 participants was conducted. Structural/construct validity was assessed on confirmatory factor analysis. The internal consistency reliability was good for the overall LSAS scale (α = 0.97) and for its original four factors (α = 0.92–0.89). The original four‐factor model fit the observed data relatively better than alternative models. These findings indicate that the LSAS is a valid and reliable measure of anxiety symptoms for this community‐dwelling population in Japan.