Validation study of the French schizotypal personality questionnaire in a sample of adolescents: a confirmatory factor analysis

Aims

This article aims to validate the schizotypal personality questionnaire in a sample of French speaking adolescents. Because early schizotypal manifestations are predictive of psychosis-proneness, reliable self-report measures are crucial for early detection of vulnerability to schizophrenia during adolescence. Unlike most existing self-reports, the questionnaire de personnalité schizotypique (SPQ) assesses individual differences in all nine feature of DSM-IV schizotypal personality (i.e. ideas of reference, excessive social anxiety, odd beliefs, unusual perceptual experience, odd behaviour, no close friends, odd speech, constricted affect and suspiciousness). Furthermore, it yields dimensional scores concerning the main schizotypal factors, which represent valuable information for the clinician's case formulation and can be used as a screening instrument in the general population.

Method

Our sample consisted of 174 adolescents (98 girls) between 12 and 17 years old. All completed the SPQ 74-item self-report. Participants were recruited in secondary schools in Switzerland, and through the child and adolescent community outpatient psychiatric service (office médico-pédagogique) affiliated to the University of Geneva's Psychiatry Department and to the Canton of Geneva Education Department. A confirmatory factorial analysis was conducted on our sample to test nine competing models of SPQ. The 3-factor model of Raine et al. was compared to concurrent 2, 3, and 4-factor models. Simple structure models of Raine et al. and Stefanis et al. were also tested.

Results

The following observations were highlighted in our results: (1) goodness-of-fit indices are better for structures allowing cross loadings than for simple structures; (2) amongst the simple structures, the best goodness-of-fit index was obtained for the Raine model and (3) the fit between our data and the Raine model is improved by a cross loading for suspiciousness subscale. The latter seems problematic for the global data fitting. This led us to test simple structures models of Siever and Gunderson, Raine et al., and Stefanis et al., based on eight subscales rather than nine. Without suspiciousness subscale, goodness-of-fit indices are enhanced in these three models. The 3-factor model yields the clearest and most reliable results in comparison with other competing models. In summary, the best goodness-of-fit indices were obtained for the 3-factor Raine model. Goodness-of-fit indices could be improved by the exclusion of the suspiciousness scale.

Conclusions

Consistent with earlier analyses by Raine et al. and Dumas et al., our data confirm the 3-factor model of the SPQ (cognitive-perceptive; interpersonal; disorganized) in a sample of French speaking adolescents. Our analyses confirm that two dimensions are insufficient to explain the structure of schizotypy during adolescence. These results further suggest the stability of a 3-factor structure during lifespan. We note that the inclusion of the suspiciousness subscales engenders statistical issues. Most studies to date have dealt with these issues by performing a cross-loading with this subscale, or by the inclusion of a paranoid factor which is linked with the negative and the cognitive-perceptive factors. We found that the most statistically sound strategy was reached without the inclusion of the suspiciousness subscale. Future studies with larger samples could investigate the SPQ structure at an item-level, which carries the benefit of reduced restrictions on the factorial analysis. In conclusion, the current study shows that the French version SPQ constitutes a reliable self-report questionnaire for the assessment of schizotypal trait expression during adolescence that may assist in the evaluation of psychosis proneness in youths.     

The validity of the Schizotypal Personality Questionnaire in a Greek sample: Tests of measurement invariance and latent mean differences

BackgroundThe Schizotypal Personality Questionnaire (SPQ) is a widely used scale for measuring schizotypal characteristics modeled on DSM-III-R criteria for schizotypal personality disorder (SPD). The aim of this study was to examine the factorial structure of the Greek SPQ, its factorial invariance across gender and different age groups and possible gender and age group differences at latent mean level.MethodsEight hundred sixty-five community participants completed the Greek version of the SPQ.ResultsWith regard to the factorial structure of the original first-order model, the results showed that a seven-factor model (sub-scales “no close friends” with “constricted affect” and “ideas of reference” with “unusual perceptual experiences” were combined) was replicated adequately. Furthermore, the second-order “paranoid” model provided also adequate fit. With regard to the factorial invariance of the SPQ across gender and age, the analysis revealed that both, the first- and second-order models showed measurement invariance (configural, metric and structural) across gender and age groups (17–35 vs. 36–70). Latent mean differences across gender and age groups were also found.ConclusionsBased on these findings, we can conclude that the Greek version of the SPQ is a psychometrically sound instrument for measuring schizotypal characteristics and a useful screening tool for SPD across gender and age.     

Three-factor model of schizotypal personality: invariance across culture, gender, religious affiliation, family adversity, and psychopathology

Whilst the syndrome approach to schizotypy has recently demonstrated differential correlates of a three-factor model of schizotypal personality, variations in the nature of these factors question a basic assumption of this approach. This study tested competing models of the factor structure of schizotypal personality using the Schizotypal Personality Questionnaire (SPQ) in a sample of 1,201 Mauritians. Factor invariance across gender, ethnicity, family adversity, and religion and across a psychopathologically select group was also assessed. Results suggest that a three-factor model, Cognitive-Perceptual Deficits, Interpersonal Deficits, and Disorganization, underlies individual differences across widely varying groups. Other competing three-factor schizotypal personality models did not fit the data better. It is argued that the three-factor Disorganized model is a well-replicated model of DSM schizotypal personality in community samples but possibly not in some clinical samples.     

The factor structure of the metabolic syndrome in obese individuals with binge eating disorder

Objective

Metabolic syndrome (MetS) is strongly linked with cardiovascular disease and type-II diabetes, but there has been debate over which metabolic measures constitute MetS. Obese individuals with binge eating disorder (BED) are one of the high risk populations for developing MetS due to their excess weight and maladaptive eating patterns, yet, the clustering patterns of metabolic measures have not been examined in this patient group.

Methods

347 adults (71.8% women) were recruited for treatment studies for obese individuals with BED. We used the VARCLUS procedure in the Statistical Analysis System (SAS) to investigate the clustering pattern of metabolic risk measures.

Results

The analysis yielded four factors: obesity (body-mass-index [BMI] and waist circumference), lipids (HDL and triglycerides), blood pressure (systolic and diastolic blood pressure), and glucose regulation (fasting serum glucose and Hb1Ac). The four factors accounted for 84% of the total variances, and variances explained by each factor were not substantially different. There was no inter-correlation between the four factors. Subgroup analyses by sex and by race (Caucasian vs. African American) yielded the same four-factor structure.

Conclusion

The factor structure of MetS in obese individuals with BED is not different from those found in normative population studies. This factor structure may be applicable to the diverse population.     

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.     

Construct validity of the Chinese version of the Chalder Fatigue Scale in a Chinese community sample

Objective

This paper aims to evaluate the factorial validity of the Chinese version of the Chalder Fatigue Scale (ChCFS) using a Chinese community sample.

Methods

A total of 201 Chinese adults completed the ChCFS, the 12-item Short-Form Health Survey (SF12), and the Hospital Anxiety and Depression Scale (HADS). Confirmatory factor analysis was conducted to assess the fit of a one-factor model, a two-factor correlated model, and a three-factor hierarchical model in both the 14-item and 11-item versions of ChCFS to the current data.

Results

ChCFS successfully replicated the original two-factor structure in the current Chinese community sample, and the 11-item version demonstrated better data-model fit than the 14-item version. The instrument possessed good internal consistency (Cronbach's α=.863). The convergent validity with HADS and divergent validity with SF12 were also evident.

Conclusions

ChCFS is valid and reliable among Chinese adults in the general population.     

中文版五条目杜克大学宗教指数量表的内部一致性和重测信度(英文)

背景:杜克大学宗教指数量表(DUREL)是一个应用广泛的宗教性评估量表,包含五个条目。目的:评估DUREL中文修订版的内部一致性、信度和因子结构。方法:宁夏回族自治区是中国西北部的一个省,其人口的34%是信奉伊斯兰教的回族。我们利用概率比例规模的抽样方法,在20个基本抽样单位中随机选出了有合适居民的3981户。3054户完成了筛查访谈并随机选出了一名成年家庭成员;2425名受访者完成了调查(包括DUREL),平均在2.5天后,188名随机选中的被试再次完成了该调查。结果:全体样本中五个条目的内部一致性(Cronbach'sα)为0.90;在依据民族、城市与农村居住地、和文化程度中位数之上下分层的被试亚组中,其值为0.70到0.90。全样本中总分的重测信度(组内相关系数)为0.87;其值在不同被试亚组中为0.63到0.90。在随机的一半样本中,探索性因子分析确定为单一因子(特征根=4.21),解释总变异的84%。在另外一半的样本中,验证性因子分析证实了单维模型;使用五条目计分的一个因子模型的模型拟合指标是可以接受的(比较拟合指数[CFI]和塔克-刘易斯指数[TLI]0.99;近似误差均方根[RMSEA]=0.105;χ2=70.49,df=5),但是将条目1和条目2(分别评估组织和个体的宗教活动)的相关作为第六个观察变量添加后,模型拟合度有改善(CFI和TLI0.99;RMSEA=0.046;χ2=14.32,df=4)。结论:中文版DUREL是一个评估宗教性的可信有效措施,可以用于评估中国受访者的宗教性/信仰与身心健康之间的关系。正如其他研究者建议,我们的因子分析结果表明总分是该量表提取的最好指标,而不是原作者建议的三个维度的评分。     

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.     

The positive and negative affect schedule: psychometric properties of the korean version

Objective

The Positive and Negative Affect Schedule (PANAS) was developed as a measure of positive affect (PA) and negative affect (NA). The aim here is to examine the factor structure and concurrent validity of the Korean version of the Positive and Negative Affect Schedule (K-PANAS) in a clinical sample in Korea.

Methods

K-PANAS was administered to a clinical sample in Korea. Internal consistency, test-retest reliability, and confirmatory factor analysis (CFA) were undertaken to examine the factorial structure and reliability of the K-PANAS.

Results

The reliability of K-PANAS is satisfactory. CFA showed that several of the models commonly used in Western populations provided an insufficient fit. The modified model provided a more adequate fit to the data.

Conclusion

The authors demonstrate that the K-PANAS has adequate psychometric properties, and that findings obtained in the West using PANAS were partially replicated.     

Confirmatory factor analysis of the short French version of the Center for Epidemiological Studies of Depression Scale (CES-D10) in adolescents

Background

Screening depressivity among adolescents is a key public health priority. In order to measure the severity of depressive symptomatology, a four-dimensional 20 items scale called “Center for Epidemiological Studies-Depression Scale” (CES-D) was developed. A shorter 10-item version was developed and validated (Andresen et al.). For this brief version, several authors supported a two-factor structure – Negative and Positive affect – but the relationship between the two reversed-worded items of the Positive affect factor could be better accounted for by correlated errors.

Objectives

The aim of this study is triple: firstly to test a French version of the CES-D10 among adolescents; secondly to test the relevance of a one-dimensional structure by considering error correlation for Positive affect items; finally to examine the extent to which this structural model is invariant across gender.

Method

The sample was composed of 269 French middle school adolescents (139 girls and 130 boys, mean age: 13.8, SD = 0.65). Confirmatory Factorial Analyses (CFA) using the LISREL 8.52 were conducted in order to assess the adjustment to the data of three factor models: a one-factor model, a two-factor model (Positive and Negative affect) and a one-factor model with specification of correlated errors between the two reverse-worded items. Then, multigroup analysis was conducted to test the scale invariance for girls and boys.

Results

Internal consistency of the CES-D10 was satisfying for the adolescent sample (α = 0.75). The best fitting model is the one-factor model with correlated errors between the two items of the previous Positive affect factor (χ²/dl = 2.50; GFI = 0.939; CFI = 0.894; RMSEA = 0.076). This model presented a better statistical fit to the data than the one-factor model without error correlation: χ²_diff (1) = 22.14, p < 0.001. Then, the one-factor model with correlated errors was analyzed across separate samples of girls and boys. The model explains the data somewhat better for boys than for girls. The model's overall χ²(68) without equality constraints from the multigroup analysis was 107.98. The χ²(89) statistic for the model with equality-constrained factor loadings was 121.31. The change in the overall Chi² is not statistically significant. This result implies that the model is, therefore, invariant across gender. The mean scores were higher for girls than boys: 9.69 versus 7.19; t(267) = 4.13, p < 0.001.

Conclusions

To conclude, and waiting for further research using the French version of the CES-D10 for adolescents, it appears that this short scale is generally acceptable and can be a useful tool for both research and practice. The scale invariance across gender has been demonstrated but the invariance across age must be tested too.     

Ethnicity and psychiatric comorbidity in a national sample: evidence for latent comorbidity factor invariance and connections with disorder prevalence

Purpose

Prevalence rates, and bivariate comorbidity patterns, of many common mental disorders differ significantly across ethnic groups. While studies have examined multivariate comorbidity patterns by gender and age, no studies to our knowledge have examined such patterns by ethnicity. Such an investigation could aid in understanding the nature of ethnicity-related health disparities in mental health and is timely given the likely implementation of multivariate comorbidity structures (i.e., internalizing and externalizing) to frame key parts of DSM-5.

Methods

We investigated whether multivariate comorbidity of 11 common mental disorders, and their associated latent comorbidity factors, differed across five ethnic groups in a large, nationally representative sample (n = 43,093). We conducted confirmatory factor analyses and factorial invariance analyses in White (n = 24,507), Hispanic/Latino (n = 8,308), Black (n = 8,245), Asian/Pacific Islander (n = 1,332), and American Indian/Alaska Native (n = 701) individuals.

Results

Results supported a two-factor internalizing–externalizing comorbidity factor model in both lifetime and 12-month diagnoses. This structure was invariant across ethnicity, but factor means differed significantly across ethnic groups.

Conclusions

These findings, taken together, indicated that observed prevalence rate differences between ethnic groups reflect ethnic differences in latent internalizing and externalizing factor means. We discuss implications for classification (DSM-5 and ICD-11 meta-structure), health disparities research, and treatment.     

Latent class analysis of the Yale-Brown Obsessive-Compulsive Scale symptoms in obsessive-compulsive disorder

Objective

Obsessive-compulsive disorder (OCD) is phenomenologically heterogeneous, and findings of underlying structure classification based on symptom grouping have been ambiguous to date. Variable-centered approaches, primarily factor analysis, have been used to identify homogeneous groups of symptoms; but person-centered latent methods have seen little use. This study was designed to uncover sets of homogeneous groupings within 1611 individuals with OCD based on symptoms.

Method

Latent class analysis models using 61 obsessive-compulsive symptoms collected from the Yale-Brown Obsessive-Compulsive Scale were fit. Relationships between latent class membership and treatment response, sex, symptom severity, and comorbid tic disorders were tested for relationship to class membership.

Results

Latent class analysis models of best fit yielded 3 classes. Classes differed only in frequency of symptom endorsement. Classes with higher symptom endorsement were associated with earlier age of onset, being male, higher Yale-Brown Obsessive-Compulsive Scale symptom severity scores, and comorbid tic disorders. There were no differences in treatment response between classes.

Conclusions

These results provide support for the validity of a single underlying latent OCD construct, in addition to the distinct symptom factors identified previously via factor analyses.     

Suicide Risk for Sexual Minorities in Middle and Older Age: Evidence From the National Survey on Drug Use and Health

Objective

No studies have estimated the difference in suicidal ideation, plans, and attempts for lesbian, gay, or bisexual (LGB) adults aged 50+ compared with heterosexuals using nationally representative data.

A population‐based,cross‐sectional study of the prevalence and correlates of sedentary behaviour of adults with intellectual disabilities

Background

High levels of sedentary behaviour have a negative impact on health and well‐being. There is limited evidence on the prevalence and correlates of sedentary behaviour of adults with intellectual disabilities (ID).

Methods

A population‐based sample of adults with ID were invited to take part in a comprehensive health check programme. Demographic and health data were collected during a structured interview and physical examination. Screen time was used as a proxy measure of sedentary behaviour. Bivariate and multivariate statistical modelling examined correlates of screen time.

Results

Fifty per cent of the 725 participants reported four or more hours of screen time per day. Male gender, higher levels of intellectual ability, mobility problems, obesity, not having hearing impairment and not having epilepsy were all significantly associated with higher screen time in the final multivariate model (R² = 0.16; Hosmer–Lemeshow goodness of fit statistic P = 0.36).

Conclusions

This is the first study to publish population‐based data on the prevalence and correlates of sedentary behaviour in adults with ID. Compared with adults who do not have ID, adults with ID have higher levels, and different correlates, of sedentary behaviour. A better understanding of the social context of sedentary behaviour will inform the design of effective behaviour change programmes for adults with ID.     

A confirmatory factor analysis of the Beck Depression Inventory-II in end-stage renal disease patients

Objective

We sought to examine several competing factor structures of the Beck Depression Inventory-II (BDI) in a sample of patients with End-Stage Renal Disease (ESRD), in which setting the factor structure is poorly defined, though depression symptoms are common. In addition, demographic and clinical correlates of the identified factors were examined.

Methods

The BDI was administered to clinical sample of 460 ESRD patients attending 4 UK renal centres. Competing models of the factor structure of the BDI were evaluated using confirmatory factor analysis.

Results

The best fitting model consisted of general depression factor that accounted for 81% of the common variance between all items along with orthogonal cognitive and somatic factors (G-S-C model, CFI = .983, TLI = .979, RMSEA = .037), which explained 8% and 9% of the common variance, respectively. Age, diabetes, and ethnicity were significantly related to the cognitive factor, whereas albumin, dialysis adequacy, and ethnicity were related to the somatic factor. No demographic or clinical variable was associated with the general factor.

Conclusion

The general-factor model provides the best fitting and conceptually most acceptable interpretation of the BDI. Furthermore, the cognitive and somatic factors appear to be related to specific demographic and clinical factors.     

The Frankfurt Complaint Questionnaire for self‐assessment of basic symptoms in the early detection of psychosis—Factor structure,reliability, and predictive validity

Objectives

Patients with schizophrenia often experience subtle disturbances in several domains of information processing—so‐called basic symptoms (BS). BS are already present before onset of frank psychosis and can be assessed by interviews but also by the self‐administered Frankfurt Complaint Questionnaire (FCQ). We investigated the factor structure, reliability, and predictive validity for transition to psychosis of the FCQ, comparing previously proposed factor solutions containing 1, 2, 4, and 10 factors.

Methods

Confirmatory factor analysis was used in a sample of 117 at‐risk mental state and 92 first‐episode psychosis participants of the Basel FePsy (early detection of psychosis) study.

Results

Although all factor models fitted to the data, the 2‐ or 4‐factor solutions performed best among the models that used at least half of the FCQ items, suggesting the covariance between FCQ items is best explained by 2 to 4 underlying factors. No FCQ‐scale predicted transition to psychosis.

Conclusion

We could confirm a 2‐ to 4‐factor structure of the FCQ in a sample of at‐risk mental state and first‐episode psychosis patients using confirmatory factor analysis. Contrary to interview‐assessed cognitive–perceptive BS, self‐assessed BS do not seem to improve prediction of psychosis. This result reinforces reports of poor correspondence between interview‐ and questionnaire‐assessed BS.

     

Validation of a Greek adaptation of the 20-item Toronto Alexithymia Scale

Background

The purpose of the current investigation was (1) to test whether the 3-factor structure of the 20-item Toronto Alexithymia Scale (TAS-20) corresponding to the theoretical conceptualization of the alexithymia construct could be recovered in a Greek translation of the scale (the TAS-20-G), (2) to assess if a 3-factor structure provides a better fit to the TAS-20-G compared with the recently proposed alternative factor structures, and (3) to evaluate the internal reliability of the TAS-20-G.

Methods

The English version of the TAS-20 was translated into Greek and then back-translated and modified until cross-language equivalence was established. The Greek version was then administered to 340 university students. Confirmatory factor analyses were conducted, and 4 different factor structure models were compared. Internal consistency and item-to-scale homogeneity of the TAS-20-G and its factor scales were also evaluated.

Results

The 3-factor model provided a good fit to the data and proved superior to alternative 1-, 2-, and 4-factor models. Apart from a coefficient α below the recommended range for the externally oriented thinking factor, the TAS-20-G and its factor scales demonstrated adequate internal consistency and homogeneity.

Conclusion

The TAS-20-G is a valid and reliable measure of alexithymia in university students and may be suitable for investigations of alexithymia in other Greek-speaking population samples.     

Establishing conversion of the 16-item Informant Questionnaire on Cognitive Decline in the Elderly scores into interval-level data across multiple samples using Rasch methodology

Background

The 16-item Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE-16) is a well-validated and widely-used measure of cognitive changes (CCs) among older adults. This study aimed to use Rasch methodology to establish psychometric properties of the IQCODE-16 and validate the existing ordinal-to-interval transformation algorithms across multiple large samples.

Methods

A Partial Credit Rasch model was employed to examine psychometric properties of the IQCODE-16 using data (n = 918) from two longitudinal studies of participants aged 57–99 years: the Older Australian Twins Study (n = 450) and the Canberra Longitudinal Study (n = 468), and reusing the Sydney Memory and Ageing Study (MAS) sample (n = 400).

Results

Initial analyses indicated good reliability for the IQCODE-16 (Person Separation Index range: 0.82–0.90). However, local dependency was identified between items, with several items showing misfit to the model. Replicating the existing Rasch solution could not reproduce the best Rasch model fit for all samples. Combining locally dependent items into three testlets resolved all misfit and local dependency issues and resulted in the best Rasch model fit for all samples with evidence of unidimensionality, strong reliability, and invariance across person factors. Accordingly, new ordinal-to-interval transformation algorithms were produced to convert the IQCODE-16 ordinal scores into interval data to improve the accuracy of its scores.

Conclusions

The findings of this study support the reliability and validity of the IQCODE-16 in measuring CCs among older adults. New ordinal-to-interval conversion tables generated using samples from multiple independent datasets are more generalizable and can be used to enhance the precision of the IQCODE-16 without changing its original format. An easy-to-use converter has been made available for clinical and research use.     

Mediating Effect of Executive Function on Memory in Normal Aging Adults

Objective

We hypothesize that the effect of aging on memory is mediated by executive function.

Methods

Two hundred and thirty healthy adults (101 male, 129 female) were recruited for the study. We used a promising, newly developed, computerized neuropsychological test for the measurement of executive function and memory. The data were analyzed using structural equation modeling and path analysis.

Results

The full mediation model showed a good fit to the data. However, chi-squared (χ²) tests for model comparison indicated that the partial mediation model better fits our data. Thus, the partial mediation model was used as the final model. In terms of auditory-verbal memory, the effect of aging on memory was fully mediated by executive function. However, visuo-spatial memory was significantly affected both indirectly (through executive function) and directly (by aging). Gender differences were not significant in this model.

Conclusion

This study demonstrated the importance of executive function in the memory functioning of normal aging adults. It is noteworthy that modality differences were found between auditory-verbal and visuo-spatial memory. Aging is not the only factor that drives memory decline, and its direct, adverse effect on memory was more prominent in the visuo-spatial memory task than auditory-verbal memory task. Since performance in both modalities is fully or partially mediated by executive function, it is important to train normal aging adults in executive control skills, such as planning, strategy formation, and rapid decision making.     

Testing comparison models of DASS-12 and its reliability among adolescents in Malaysia

Objective

The 21-item Depression, Anxiety and Stress Scale (DASS-21) is frequently used in non-clinical research to measure mental health factors among adults. However, previous studies have concluded that the 21 items are not stable for utilization among the adolescent population. Thus, the aims of this study are to examine the structure of the factors and to report on the reliability of the refined version of the DASS that consists of 12 items.

Method

A total of 2850 students (aged 13 to 17 years old) from three major ethnic in Malaysia completed the DASS-21. The study was conducted at 10 randomly selected secondary schools in the northern state of Peninsular Malaysia. The study population comprised secondary school students (Forms 1, 2 and 4) from the selected schools.

Results

Based on the results of the EFA stage, 12 items were included in a final CFA to test the fit of the model. Using maximum likelihood procedures to estimate the model, the selected fit indices indicated a close model fit (χ² = 132.94, df = 57, p = .000; CFI = .96; RMR = .02; RMSEA = .04). Moreover, significant loadings of all the unstandardized regression weights implied an acceptable convergent validity. Besides the convergent validity of the item, a discriminant validity of the subscales was also evident from the moderate latent factor inter-correlations, which ranged from .62 to .75. The subscale reliability was further estimated using Cronbach's alpha and the adequate reliability of the subscales was obtained (Total = 76; Depression = .68; Anxiety = .53; Stress = .52).

Conclusion

The new version of the 12-item DASS for adolescents in Malaysia (DASS-12) is reliable and has a stable factor structure, and thus it is a useful instrument for distinguishing between depression, anxiety and stress.