Four-dimensional Factor Structure Research Articles

Development and psychometric properties of the Health Anxiety Behavior Inventory (HABI).

Mainstream cognitive behavioural theory stipulates that clinically significant health anxiety persists over time at least partially due to negatively reinforced health-related behaviours, but there exists no broad and psychometrically valid measure of such behaviours. To draft and evaluate a new self-report scale - the Health Anxiety Behavior Inventory (HABI) - for the measurement of negatively reinforced health anxiety behaviours. We drafted the HABI from a pool of 20 candidate items administered in a clinical trial at screening, and before and after cognitive behaviour therapy (n=204). A psychometric evaluation focused on factor structure, internal consistency, convergent and discriminant validity, test-retest reliability, and sensitivity to change. Based on factor analysis, the HABI was completed as a 12-item instrument with a four-dimensional factor structure corresponding to the following scales: (i) bodily preoccupation and checking, (ii) information- and reassurance-seeking, (iii) prevention and planning, and (iv) overt avoidance. Factor inter-correlations were modest. The internal consistency (α=.73-.87) and 2-week test-retest reliability (r=.75-.90) of the scales was adequate. The bodily preoccupation and checking, and information- and reassurance-seeking scales were most strongly correlated with the cognitive and emotional components of health anxiety (r=0.41, 0.48), and to a lower extent correlated to depressive symptoms and disability. Change scores in all HABI scales correlated with improvement in the cognitive and emotional components of health anxiety during cognitive behaviour therapy. The HABI appears to reliably measure negatively reinforced behaviours commonly seen in clinically significant health anxiety, and might be clinically useful in the treatment of health anxiety.

Construction and First Validation of a French Scale of Environmental Harassment at Work (EHWS)

Harassment is a form of violence that is increasingly reported in the world of work and has given rise to numerous studies. This article presents the results of a series of five studies to construct and validate the French Environmental Harassment at Work Scale-EHWS. Four hundred and four people employed in various professional sectors (health, education, or services) participated in the five studies. A questionnaire on Environmental Harassment at Work was constructed (Study 1). Study 2 revealed a four-dimensional factor structure, which was confirmed by confirmatory factor analysis (Study 3). The questionnaire was shown to have good reliability (Study 4) and convergent validity (Study 5). The EHWS could be a valuable tool for human resource managers to assess environmental harassment in the organisation, and also for occupational health and safety organisations to highlight the nature of environmental harassment, and how it can be reported and prevented.

Perceived forcedness and perils of migration: Development and validation of a questionnaire for residents in receiving countries

ObjectivesFor refugees in receiving countries, integration is a growing challenge, and a core factor in this process is residents’ perceptions of refugees. This study examines whether perceived forcedness of migration affects residents’ reactions to new members of society. In doing so, we introduce a new questionnaire to assess forcedness and perils of migration as perceived by residents of receiving countries. The PMF-Res (Perceived Migration Forcedness – Residents) allows one to compare residents’ reactions to refugees and non-refugee migrants. MethodsIn Study 1 (N1 = 925; 39% male, 60% female, 1% non-binary; age: M = 45.44; SD = 16.30), we piloted theoretically derived items and examined their underlying factor structure. Study 2 (N2 = 1056; 41% male, 57% female, 1% non-binary, 1% no information; age: M = 50.69; SD = 14.54) replicated these results with an independent sample and further analyzed the psychometric properties of the new measure. ResultsStudy 1 supported the assumed four-dimensional factor structure (i.e., perceived locus of causality; perceived options for choice; perceived pre-migration perils; and perceived migration perils). Study 2 replicated this structure with an independent sample and an experimental design. Furthermore, results provided strong evidence for reliability, construct validity, and sensitivity of the new measure. ConclusionsThe new PMF-Res offers a reliable, valid, and efficient measure to assess forcedness and perils of migration from the perspective of receiving countries’ residents, and the PMF-Res may be used for both research and applied purposes.

Validation of the factor structure and psychometric characteristics of the Arabic adaptation of the sense of coherence SOC-13 scale: a confirmatory factor analysis

BackgroundThe sense of coherence is as focused on one’s awareness of the level of pervasive, enduring, and dynamic feelings. Stronger sense of coherence leads to better physical and mental health and promotes recovery from life stressors. Sense of coherence-13 (SOC-13) is a 13-item valid and reliable measure for individual’s healthy living. However, the factor structure of SOC-13 was criticized in several cultures and languages. The current study was set to explore the factor structure of an Arabic adaptation for SOC-13.MethodsThis cross-sectional study of the SOC-13 included (n = 1235) Arabic speaking individuals. We used confirmatory factor analysis to contrast unidimensional, bidimensional, three-dimensional, and four-dimensional factor structure for the SOC-13. We carried out measurement invariance analysis across age and gender groups to examine the stability of fit indices among participants’ subgroups.ResultsWe found the reliability coefficient to be 0.82, indicative of good internal consistency. The three-factor structure, after modification of items 1, 2, and 3 was the best-fitting factor model. However, measurement invariance was indicative of discrepancy for the three-factor model between genders and age classes. The mean overall SOC-13 total score in our sample was 52.1 (SD = 16.1).ConclusionsThe SOC-13 showed acceptable psychometric properties in terms of internal consistency and a modified three-factor structure in its Arabic version. However, the reliability of the three underlying dimensions was sub-optimum. Moreover, the three-factor structure requires modification by either removing the first three problematic items or allowing the residuals to correlate.

“Fort Aux Fesses”, “Fort Aux Poches”, “Fort Au Cœur”: Buzz or Reality? Initial Validation of Love Scale French Version and Effect of Women’s Mate Profile on Their Love and Happiness

This research structured in two studies had as main objective to study the effect of women’s mate profile on their love and happiness. It was conducted with a French-speaking Cameroonian sample. In the absence of a French-language love scale available in literature, one had to be validated. The first study was therefore intended to validate in a Cameroonian context, the French version of love scale. The results showed the French version has psychometric qualities which testify to its adjustment in Cameroonian context with a four-dimensional factor structure and 19 items. That tool made it possible to undertake the second study, which aimed to test the priming effect of the feeling of having a partner with a profile “fort aux fesses” vs. “fort aux poches” vs. “fort au cœur” on women love and happiness. According with hypothesis results showed that none of these profiles makes women more in love and/or happier at the expense of other profiles. The idea of a standard woman’ mate profile which would provide a certain degree of love and happiness seems irrelevant as evolutionary psychology argues. The debate which has inflamed social networks in Cameroon, tending to maintain that a “fort aux fesses” partner makes women more in love and/or happier at the expense of other partner profiles would be a “buzz”. This research enriches the literature on the evolutionary psychological perspective contribution in the study of romantic relationship.

Construct validity and psychosocial correlates of the Italian version of the 21-item Medical Interview Satisfaction Scale in primary care

Satisfaction with the medical interview has been rarely explored in primary care outside the UK, despite evidence suggesting that a trustful doctor-patient relationship is a key ingredient to facilitate treatment adherence and relief from illness-related distress. The aims of this study are to analyse the construct validity of the Italian version of the Medical Interview Satisfaction Scale (MISS-21) and its correlations with two outcome measures, the Inventory of Depressive Symptomatology - Self-Report and World Health Organization Quality Of Life Brief Version, in patients with mild-to-moderate depression, recruited in primary care practices. The factor structure underlying the MISS-21 was investigated with principal component analysis, and the internal consistency of the factors was evaluated with Cronbach's alpha. Network analysis was used to investigate the interrelationships among items. The importance of individual items in the network structure was determined with centrality analyses. Correlations of MISS-21 scores with changes in depression and quality of life were analysed with Spearman's correlation coefficient. The MISS-21 proved to have a robust four-dimensional factor structure. Cronbach's alpha for the factors ranged from 0.77 to 0.93, suggesting good to excellent internal consistency. The four factors identified were positively correlated with improvement in depressive symptoms and three quality-of-life domains. The MISS-21 has sound psychometric properties, and comprises four factors related to clinical outcomes, which makes it suitable for clinical and research applications. The central items in the network should be considered as possible targets for quality improvement interventions in primary care.

Measuring Difficulties in Choosing an Upper Secondary School: Validating of the Parental Expectations, Confusion, Anxiety and Suitability Scale (PeCAS Scale).

This study was aimed to develop a new questionnaire, on school choice difficulties, with a limited number of items and scales to make it suitable both for pre-screening on large numbers of students and studies which use batteries of many tests. The PeCAS Scale assesses four dimensions, Parental expectations, Confusion, Anxiety, and Suitability, which could be considered the most essential according to previous literature. In total, 1495 students participated in the study. Both exploratory and confirmatory factor analysis supported a four-dimensional factor structure. Reliability and concurrent validity, concerning the process of choosing a school and a scale on career exploration, were also adequate.

The Use of Demoralization Scale in Italian Kidney Transplant Recipients.

Demoralization is a commonly observed syndrome in medically ill patients. The risk of demoralization may increase in patients after a kidney transplant (KTRs) because of the stressful nature of renal transplantation, psychosocial challenges, and adjustment needs. No study is available on demoralization amongst KTRs. The purpose of our study was to evaluate the validity of the Italian version of the Demoralization Scale (DS-IT) and the prevalence of demoralization in KTRs. Also, we aimed at exploring the association of the DS-IT with International Classification of Diseases (ICD) psychiatric diagnoses, post-traumatic growth (PTG), psychological and physical symptoms, and daily-life problems. A total of 134 KTRs were administered the MINI International Neuropsychiatric Interview 6.0. and the Diagnostic Criteria for Psychosomatic Research–Demoralization (DCPR/D) Interview. The DS-IT, the Edmonton Symptom Assessment System (ESAS), the Canadian Problem Checklist (CPC), were used to measure demoralization, physical and psychological symptoms, and daily-life problems; also, positive psychological experience of kidney transplantation was assessed with the PTG Inventory. Routine biochemistry and sociodemographic data were collected. Exploratory factor analysis demonstrated a four-dimensional factor structure of the DS-IT, explaining 55% of the variance (loss of meaning and purpose, disheartenment, dysphoria, and sense of failure). DS-IT Cronbach alpha coefficients indicated good or acceptable level of internal consistency. The area under the Receiving Operating Characteristics (ROC) curve for DS-IT (against the DCPR/D interview as a gold standard) was 0.92. The DS-IT optimal cut-off points were ≥20 (sensitivity 0.87, specificity 0.82). By examining the level of demoralization, 14.2%, 46.3%, 24.6%, and 14.6% of our sample were classified as having no, low, moderate, and high demoralization, respectively, with differences according to the ICD psychiatric diagnoses (p < 0.001). DS-IT Total and subscales scores were positively correlated with scores of ESAS symptoms and CPC score. A correlation between DS-IT loss of meaning and purpose subscale and PTGI appreciation of life subscale (p < 0.05) was found. This study shows, for the first time, a satisfactory level of reliability of the DS-IT and a high prevalence of severe demoralization in KTRs.

Trans-Cultural Validation of the “Academic Flow Scale” (Flow 4D 16) in Arabic Language: Insights for Occupational and Educational Psychology From an Exploratory Study

Background: As an optimal psychological state, flow represents those moments when everything comes together for the performer. Flow is often associated with high levels of performance and is a positive psychological experience.Aim: Our study aimed to validate the “Academic Flow Scale” (Flow 4D 16) in Arabic language across Tunisian population, and to test its factor structure, in terms of internal consistency/reliability, predictive validity, and sensitivity.Methods: The population is composed of 320 students (139 men and 181 women) belonging to the University of Sfax, with a mean age of 22.26 years. The students voluntarily responded to the scale of academic flow (Flow 4D 16). Both exploratory (EFA) and confirmatory (CFA) factor analyses were performed.Results: The four-dimensional alpha coefficients of the Flow 4D 16 indicate an excellent internal consistency, respectively, of 0.902 (Cognitive), 0.959 (Time), 0.974 (Ego) and 0.960 (Well-being). The CFA fit indices were satisfactory.Conclusion: In summary, the 16-items model (original version) showed for all the indices an excellent fit to the theoretical model, confirming the four-dimensional factor structure among Tunisian student population.

A multimodal measure of cultural intelligence for adolescents growing up in culturally diverse societies

Adolescents growing up in culturally diverse societies need to develop intercultural competence. To better understand how to develop intercultural competence we need measures specifically relating to the everyday intercultural experiences of adolescents. However, few measures of intercultural competence are available for this target group. Based on the cultural intelligence (CQ) model (Earley & Ang, 2003), we developed a measure that combines a self-report questionnaire and situational judgment tests (SJTs). The latter comprise a brief description of intercultural situations, followed by questions asking the adolescents to interpret and provide a reaction to the situations.The reliability, factor structure, measurement equivalence, and validity of the new measure was tested in two samples of adolescents in culturally diverse regions in North Rhine-Westphalia (N = 631, 48% female, Mage = 13.69 years, SDage = 1.83) and Berlin (N = 1,335, 48% female, Mage = 14.69 years, SDage = 0.74) in Germany. The self-report CQ scale showed good reliability and a four-dimensional factor structure with a higher-order CQ factor. The responses to the SJTs were coded based on a coding manual and the ratings loaded onto one factor. The measurement models showed metric to scalar measurement equivalence across immigrant background, gender, and grade. The CQ factor and the SJT factor were positively correlated with each other, as well as with related constructs such as openness, perspective-taking, and diversity beliefs.We conclude that the new measure offers a reliable and valid method to assess the intercultural competence of adolescents growing up in culturally diverse societies.

Development and Validation of the Amphetamine-Type Stimulants Motive Questionnaire in a Clinical Population.

Approximately 35.7 million people world-wide use amphetamine-type stimulants (ATS) leading to a high demand for effective treatment. Understanding the motives behind ATS use is a necessary basis for preventive and therapeutic treatment. The objective of this study is to develop the Amphetamine-Type stimulants Motive Questionnaire (AMQ) and to confirm its construct and concurrent validity in respect to the first and the latest month of ATS use based on answers of 233 patients with ATS disorders (74.2% male; mean age: 31.1 years). Confirmatory factor analyses were employed to test for the construct validity of the AMQ. Nested models of confirmatory factor analyses with increasing constraints for gender and age were estimated to test the equivalence of the factor structure in different subgroups. Independent sample t-tests were conducted to test for mean differences in the motive dimensions. A structural equation model was estimated to confirm the concurrent validity using the latent four motive factors (i.e., enhancement, coping, social, and conformity motives) as independent variables and frequency of ATS use in the first and the latest month of use as a dependent variable. The results confirmed the AMQ’s four-dimensional factor structure in general, and across gender and age groups for both periods of time. Men (first month: M = 4.21, SD = 0.75; latest month: M = 3.86, SD = 0.93) use ATS more frequently due to enhancement motives than women (first month: M = 3.85, SD = 1.12; latest month: M = 3.46, SD = 1.29) at both periods of time [first month: t(77) = −2.33, p = 0.022; latest month: t(80) = −2.19, p = 0.031]. Structural equation modeling confirmed an association between coping motives and use frequency, for both periods of time (first and latest month: β = 0.32, p < 0.001), as well as between social motives and frequency of use for the latest month of use (β = 0.30, p < 0.01). To conclude, the AMQ is a valid and reliable instrument for assessing motives of ATS use in a clinical population. It can provide important insights into the motivational structure of the first and latest months of ATS use which are useful for preventive and therapeutic treatments as well as the development of abstinence skills.

An Exploration of the Four-Factor Structure of the Drinking Motives Questionnaire-Revised Among Undergraduate Students in China

Background: College drinking has become a significant health issue in China; the current study addressed the gap that no prior research has investigated drinking motives among Chinese undergraduate students. Objectives: This study aimed to replicate the four-factor structure of the Drinking Motives Questionnaire-Revised (DMQ-R) reported for Western populations. Additionally, the relationships between drinking motives and alcohol use were investigated. Methods: In 2012, 436 participants (mean age = 20.49 and SD = 1.49; 50% male) recruited from a college in China completed a self-administered survey in their classroom setting. Drinking motives were measured by the Chinese version of the DMQ-R; three indicators of alcohol use were assessed. Factor analysis was conducted to examine the factor structure of the DMQ-R, followed by regression analysis to investigate the associations between drinking motives and alcohol-related outcomes. Results: Confirmatory factor analysis failed to replicate the measurement model tested, but exploratory factor analysis identified a similar four-dimensional factor structure. Reliability and convergent and discriminant validity of the four factors were acceptable. The results also showed that social motives were related to alcohol use and heavy drinking; conformity motives were related to alcohol use and alcohol-related problems. Enhancement motives were the strongest correlates of alcohol use; coping motives were the strongest correlates of heavy drinking and alcohol-related problems. Conclusions/Importance: The DMQ-R was a reliable and valid scale measuring four types of drinking motives among Chinese college students. Findings suggested that the motivational model of alcohol use may apply to studying college drinking in China.

Comparing Dutch and British high performing managers

AbstractNational cultures have a strong influence on the performance of organizations and should be taken into account when studying the traits of high performing managers. At the same time, many studies that focus upon the attributes of successful managers show that there are attributes that are similar for managers across countries. This article reports on the development of empirically validated profiles of Dutch and British high performing managers. Based on a sample of 808 Dutch and 286 British managers and using the cross-cultural framework of Excellent Leadership by Selvarajah et al., the profiles of excellent Dutch and British managers was derived. The profiles of Dutch and British high performing managers can be described by a four-dimensional factor structure consisting of Managerial behaviours, Environmental influences, Personal qualities and Organizational demands. Based on these validated profiles, the similarities and differences in attributes for managerial success between Dutch and British high performing managers can be identified.

Development of the four-dimensional Motives for Listening to Music Questionnaire (MLMQ) and associations with health and social issues among adolescents

In order to develop the Motives for Listening to Music Questionnaire (MLMQ) and to confirm its construct and concurrent validity, data from a nationally representative sample of 4,524 adolescents in Switzerland were used. The results confirmed the MLMQ’s four-dimensional factor structure (i.e., social, enhancement, coping and conformity motives) in general and across gender, age and linguistic region. Girls listened to music more frequently for coping, enhancement and social motives than boys. Structural equation modelling confirmed the hypothesized associations between coping motives and health-related outcomes (somatic complaints, aggressive and depressed mood, school pressure, low life satisfaction etc.), between social motives and peer-related activities (spending evenings with friends, bullying others etc.), and between conformity motives and being depressed and a victim of bullying. To conclude, confirming its psychometric qualities, the MLMQ is a valid and reliable instrument for assessing music motives in adolescent populations. In health care, the MLMQ could be used to identify individuals and to help applying music therapy in accordance with their motives for listening to music.

Drinking motives and links to alcohol use in 13 European countries.

The purpose of this study was to test the structure and endorsement of drinking motives and their links to alcohol use among 11- to 19-year-olds from 13 European countries. Confirmatory factor analysis, latent growth curves, and multiple regression models were conducted, based on a sample of 33,813 alcohol-using students from Belgium, Denmark, Estonia, Finland, Hungary, Ireland, Italy, Poland, Portugal, Scotland, Slovakia, Switzerland, and Wales who completed the Drinking Motives Questionnaire Revised Short Form (DMQ-R SF). The findings confirmed the hypothesized fourdimensional factor structure. Social motives for drinking were most frequently indicated, followed by enhancement, coping, and conformity motives, in that order, in all age groups in all countries except Finland. This rank order was clearest among older adolescents and those from northern European countries. The results confirmed that, across countries, social motives were strongly positively related to drinking frequency, enhancement motives were strongly positively related to frequency of drunkenness, and conformity motives were negatively related to both alcohol outcomes. Against our expectations, social motives were more closely related to drunkenness than were coping motives, particularly among younger adolescents. The findings reveal striking cross-cultural consistency. Health promotion efforts that are based on, or incorporate, drinking motives are likely to be applicable across Europe. As social motives were particularly closely linked to drunkenness among young adolescents, measures to impede the modeling of alcohol use and skills to resist peer pressure are particularly important in this age group.

Development and Validation of the Drinking Motive Questionnaire Revised Short Form (DMQ–R SF)

A short form of the Drinking Motive Questionnaire Revised (DMQ–R; Cooper, 1994) was developed, using different item selection strategies based on a national representative sample of 5,617 12- to 18-year-old students in Switzerland. To confirm the concurrent validity of the short-form questionnaire, or DMQ–R SF, data from a second national sample of 2,398 12- to 17-year-old students were analyzed by means of structural equation modeling. The results confirmed the four-dimensional factor structure of the DMQ–R SF both in general and among subpopulations. The mean values as well as the links with alcohol use and related problems were similar to those obtained with the original DMQ–R. These results support the potential use of the DMQ–R SF in a wide range of international studies that measure drinking motives.

How Stable Is the Motive–Alcohol Use Link? A Cross-National Validation of the Drinking Motives Questionnaire Revised Among Adolescents From Switzerland, Canada, and the United States

The aim of this study was to investigate cross-national differences (1) in the four-dimensional factor structure of drinking motives; (2) in the mean levels of enhancement, coping, social, and conformity motives; and (3) in the association of these motives with adolescent alcohol use, risky single-occasion drinking, and alcohol-related problems. Confirmatory factor analysis, analysis of variance, and structural equation modeling were applied to sample data from Switzerland (n=5,118; mean age=15.3), Canada (n=2,557; mean age=15.7), and the United States (n=607; mean age=15.7). The results showed that the four-dimensional factor structure of the Drinking Motives Questionnaire Revised (DMQ-R) was structurally invariant across the three countries. Although the rank order in mean levels of motive endorsement was the same across countries (i.e., highest for social, followed by enhancement, coping, and conformity), the absolute levels of endorsement were highest in the Canadian sample, followed by the Swiss and then the U.S. sample. In all three countries, enhancement and coping motives were positively related to alcohol use and to risky drinking in particular, and coping motives were additionally related to alcohol-related problems. The results indicate that the DMQ-R is a valid and reliable instrument to assess drinking motives across cultures. It appears therefore that the DMQ-R is an ideal instrument for inclusion in large cross-national surveys and that programs that target motives as a way to reduce risky drinking may be appropriate for different drinking cultures in different geographical locations.

Replication and Validation of the Drinking Motive Questionnaire Revised (DMQ-R, Cooper, 1994) among Adolescents in Switzerland

This paper has two aims: (1) to replicate the four-dimensional structure of the Drinking Motive Questionnaire Revised (DMQ-R) in a national representative sample from Switzerland, and (2) to validate the relevance of distinguishing drinking motives by inspecting the relations with expected consequences, alcohol use, and alcohol-related and other problems. Confirmatory factor analysis and linear structural equation models were estimated based on answers of 5,617 8th to 10th graders (mean 15.1 years; SD = 0.95). The results confirm the four-dimensional factor structure in general and among subpopulations defined by gender, age, and linguistic region. It could also be confirmed that enhancement motives followed by coping motives were strongly related to alcohol use and heavy drinking, whereas conformity motives were negatively related. Coping motives were related to problems independent of whether they were assessed as alcohol-related or not, while enhancement motives were associated solely with alcohol-related problems. In sum, the results demonstrate the robustness of the DMQ-R and its usefulness for assessing drinking motives among European adolescents from different cultural backgrounds.

TEMPS-I: delineating the most discriminant traits of the cyclothymic, depressive, hyperthymic and irritable temperaments in a nonpatient population

Background: Although most personality constructs have been standardized in population studies, cyclothymic, depressive, irritable and hyperthymic temperaments putatively linked to mood disorders have been classically derived from clinical observations. Methods: We therefore administered the semi-structured affective temperament schedule of Memphis, Pisa, Paris and San Diego, Interview version (TEMPS-I) — in its original University of Tennessee operationalization — to 1010 Italian students aged between 14 and 26. The interview, administered in a randomized format, took 20 min per subject. Results: The semi-structured interview was easy to administer and well accepted by subjects, with no refusals. Principal component analysis with varimax rotation confirmed the hypothesized four-dimensional factor structure of the interview, with good to excellent internal consistency. Furthermore, discriminant analysis and multiple regression provided suggestions for identifying the traits that are most useful in defining a weighted cut-off for each of the temperaments (and which, with minor exceptions, are in agreement with those previously proposed on clinical grounds). In an additional exploratory factorial analysis, a depressive type which loads negatively on hyperthymia was distinguished from cyclothymia; the irritable temperament did not appear to have significant loading on either factor. Limitation: All the present analyses were internal to the scale itself, but ongoing studies are comparing them with other systems of temperament as well as testing their clinical cogency for affectively ill populations. Conclusion: While more work needs to be done on better operationalization of the irritable temperament, our findings overall support the existence — in a relatively young nonpatient population — of cyclothymic, depressive and hyperthymic types according to the classic descriptions of Kraepelin, Kretschmer and Schneider, in their TEMPS-I operationalization. Clinical implications: Coupled with a previous report identifying 10% of the same 14–26-year-old nonpatient population meeting an empirically defined statistical cut-off for these temperaments, the present data define the putative `fundamental states' that Kraepelin considered to be the personal predisposing anlagé of major affective disorders.