Michael Chmielewski

Development and Validation of the Inventory of Depression and Anxiety Symptoms (IDAS)

The authors describe a new self-report instrument, the Inventory of Depression and Anxiety Symptoms (IDAS), which was designed to assess specific symptom dimensions of major depression and related anxiety disorders. They created the IDAS by conducting principal factor analyses in 3 large samples (college students, psychiatric patients, community adults); the authors also examined the robustness of its psychometric properties in 5 additional samples (high school students, college students, young adults, postpartum women, psychiatric patients) who were not involved in the scale development process. The IDAS contains 10 specific symptom scales: Suicidality, Lassitude, Insomnia, Appetite Loss, Appetite Gain, Ill Temper, Well-Being, Panic, Social Anxiety, and Traumatic Intrusions. It also includes 2 broader scales: General Depression (which contains items overlapping with several other IDAS scales) and Dysphoria (which does not). The scales (a) are internally consistent, (b) capture the target dimensions well, and (c) define a single underlying factor. They show strong short-term stability and display excellent convergent validity and good discriminant validity in relation to other self-report and interview-based measures of depression and anxiety.

The Reliability and Validity of Discrete and Continuous Measures of Psychopathology: A Quantitative Review.

In 2 meta-analyses involving 58 studies and 59,575 participants, we quantitatively summarized the relative reliability and validity of continuous (i.e., dimensional) and discrete (i.e., categorical) measures of psychopathology. Overall, results suggest an expected 15% increase in reliability and 37% increase in validity through adoption of a continuous over discrete measure of psychopathology alone. This increase occurs across all types of samples and forms of psychopathology, with little evidence for exceptions. For typical observed effect sizes, the increase in validity is sufficient to almost halve sample sizes necessary to achieve standard power levels. With important caveats, the current results, considered with previous research, provide sufficient empirical and theoretical basis to assume a priori that continuous measurement of psychopathology is more reliable and valid. Use of continuous measures in psychopathology assessment has widespread theoretical and practical benefits in research and clinical settings.

Further validation of the IDAS: Evidence of Convergent, Discriminant, Criterion, and Incremental Validity

The authors explicated the validity of the Inventory of Depression and Anxiety Symptoms (IDAS; D. Watson et al., 2007) in 2 samples (306 college students and 605 psychiatric patients). The IDAS scales showed strong convergent validity in relation to parallel interview-based scores on the Clinician Rating version of the IDAS; the mean convergent correlations were .51 and .62 in the student and patient samples, respectively. With the exception of the Well-Being Scale, the scales also consistently demonstrated significant discriminant validity. Furthermore, the scales displayed substantial criterion validity in relation to Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV; American Psychiatric Association, 1994) mood and anxiety disorder diagnoses in the patient sample. The authors identified particularly clear and strong associations between (a) major depression and the IDAS General Depression, Dysphoria and Well-Being scales, (b) panic disorder and IDAS Panic, (c) posttraumatic stress disorder and IDAS Traumatic Intrusions, and (d) social phobia and IDAS Social Anxiety. Finally, in logistic regression analyses, the IDAS scales showed significant incremental validity in predicting several DSM-IV diagnoses when compared against the Beck Depression Inventory-II (A. T. Beck, R. A. Steer, & G. K. Brown, 1996) and the Beck Anxiety Inventory (A. T. Beck & R. A. Steer, 1990).

Development of a measure of experiential avoidance: The Multidimensional Experiential Avoidance Questionnaire.

Experiential avoidance (EA) has been conceptualized as the tendency to avoid negative internal experiences and is an important concept in numerous conceptualizations of psychopathology as well as theories of psychotherapy. Existing measures of EA have either been narrowly defined or demonstrated unsatisfactory internal consistency and/or evidence of poor discriminant validity vis-à-vis neuroticism. To help address these problems, we developed a reliable self-report questionnaire assessing a broad range of EA content that was distinguishable from higher order personality traits. An initial pool of 170 items was administered to a sample of undergraduates (N = 312) to help evaluate individual items and establish a structure via exploratory factor analyses. A revised set of items was then administered to another sample of undergraduates (N = 314) and a sample of psychiatric outpatients (N = 201). A 2nd round of item evaluation was performed, resulting in a final 62-item measure consisting of 6 subscales. Cross-validation data were gathered in 3 new, independent samples (students, N = 363; patients, N = 265; community adults, N = 215). The resulting measure (the Multidimensional Experiential Avoidance Questionnaire, or MEAQ) exhibited good internal consistency, was substantially associated with other measures of avoidance, and demonstrated greater discrimination vis-à-vis neuroticism relative to preexisting measures of EA. Furthermore, the MEAQ was broadly associated with psychopathology and quality of life, even after controlling for the effects of neuroticism.

What is being assessed and why it matters: the impact of transient error on trait research.

Temporal instability can reflect either true psychological change or transient measurement error, and it is important that trait psychologists be able to distinguish one from the other. The authors report results from large retest studies of Big Five, trait affectivity, and personality disorder measures across time frames (2 months and 2 weeks) over which these constructs should show little or no true change. On average, nearly 25% of the variance in the measures was a product of transient error rather than true change; however, the proportion of error varied widely-but consistently-across measures. In addition, a reexamination of long-term longitudinal data demonstrated that ignoring transient error can lead to inaccurate conclusions. Most notably, a substantial portion of the observed instability in the Big Five and trait affectivity is due to transient error; thus, these traits are even more stable than commonly thought. The present data further suggest that previous reports of differential stability between the Big Five and trait affectivity are due, in part, to differential levels of transient error in measures of these constructs.

The Psychometric Properties of the Personality Inventory for DSM-5 in an APA DSM-5 Field Trial Sample:

Section 3 of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) includes a hybrid model of personality pathology, in which dimensional personality traits are used to derive one of seven categorical personality disorder diagnoses. The Personality Inventory for DSM-5 (PID-5) was developed by the DSM-5 Personality and Personality Disorders workgroup and their consultants to produce a freely available instrument to assess the personality traits within this new system. To date, the psychometric properties of the PID-5 have been evaluated primarily in undergraduate student and community adult samples. In the current investigation, we extend this line of research to a psychiatric patient sample who participated in the APA DSM-5 Field Trial (Centre for Addiction and Mental Health site). A total of 201 psychiatric patients (102 men, 99 women) completed the PID-5 and the Revised NEO Personality Inventory (NEO PI-R). The internal consistencies of the PID-5 domain and facet trait scales were acceptable. Results supported the unidimensional structure of all trait scales but one, and the convergence between the PID-5 and analogous NEO PI-R scales. Evidence for discriminant validity was mixed. Overall, the current investigation provides support for the psychometric properties of this diagnostic instrument in psychiatric samples.

Openness to Experience, Intellect, Schizotypal Personality Disorder, and Psychoticism: Resolving the Controversy

Section III of DSM-5 includes an alternative model for personality disorders comprising five higher-order pathological personality traits, four of which resemble domains from the Big Five/Five-Factor Model of Personality (FFM). There has, however, been considerable debate regarding the association of FFM Openness-to-Experience/Intellect (OE/I) with DSM-5 Psychoticism and Schizotypal Personality Disorder (STPD). The authors identify several limitations in the literature, including inattention to (a) differences in the conceptualization of OE/I in the questionnaire and lexical traditions and (b) the symptom heterogeneity of STPD. They then address these limitations in two large patient samples. The results suggest that OE/I per se is weakly associated with Psychoticism and STPD symptoms. However, unique variance specific to the different conceptualizations of OE/I demonstrates much stronger associations, often in opposing directions. These results clarify the debate and the seemingly discrepant views that OE/I is unrelated to Psychoticism and contains variance relevant to Psychoticism.

The brief experiential avoidance questionnaire: development and initial validation.

The 62-item Multidimensional Experiential Avoidance Questionnaire (MEAQ) was recently developed to assess a broad range of experiential avoidance (EA) content. However, practical clinical and research considerations made a briefer measure of EA desirable. Using items from the original 62-item MEAQ, a 15-item scale was created that tapped content from each of the MEAQs six dimensions. Items were selected on the basis of their performance in 3 samples: undergraduates (n = 363), psychiatric outpatients (n = 265), and community adults (n = 215). These items were then evaluated using 2 additional samples (314 undergraduates and 201 psychiatric outpatients) and cross-validated in 2 new, independent samples (283 undergraduates and 295 community adults). The resulting measure (Brief Experiential Avoidance Questionnaire; BEAQ) demonstrated good internal consistency. It also exhibited strong convergence with respect to each of the MEAQs 6 dimensions. The BEAQ demonstrated expected associations with measures of avoidance, psychopathology, and quality of life and was distinguishable from negative affectivity and neuroticism.

The value of suppressor effects in explicating the construct validity of symptom measures.

Suppressor effects are operating when the addition of a predictor increases the predictive power of another variable. We argue that suppressor effects can play a valuable role in explicating the construct validity of symptom measures by bringing into clearer focus opposing elements that are inherent--but largely hidden--in the measures overall score. We illustrate this point using theoretically grounded, replicated suppressor effects that have emerged in analyses of the original Inventory of Depression and Anxiety Symptoms (IDAS; Watson et al., 2007) and its expanded 2nd version (IDAS-II; Watson et al., 2012). In Study 1, we demonstrate that the IDAS-II Appetite Gain and Appetite Loss scales contain both (a) a shared distress component that creates a positive correlation between them and (b) a specific symptom component that produces a natural negative association between them (i.e., people who recently have experienced decreased interest in food/loss of appetite are less likely to report a concomitant increase in appetite/weight). In Study 2, we establish that mania scales also contain 2 distinct elements-namely, high energy/positive emotionality and general distress/dysfunction-that oppose each another in many instances. In both studies, we obtained evidence of suppression effects that were highly robust across different types of respondents (e.g., clinical outpatients, community adults, college students) and using both self-report and interview-based measures. These replicable suppressor effects establish that many homogeneous, unidimensional symptom scales actually contain distinguishable components with distinct--at times, even antagonistic--properties.

Associations between DSM-5 section III personality traits and the Minnesota Multiphasic Personality Inventory 2-Restructured Form (MMPI-2-RF) scales in a psychiatric patient sample.

Our aim in the current study was to evaluate the convergence between Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5) Section III dimensional personality traits, as operationalized via the Personality Inventory for DSM-5 (PID-5), and Minnesota Multiphasic Personality Inventory 2-Restructured Form (MMPI-2-RF) scale scores in a psychiatric patient sample. We used a sample of 346 (171 men, 175 women) patients who were recruited through a university-affiliated psychiatric facility in Toronto, Canada. We estimated zero-order correlations between the PID-5 and MMPI-2-RF substantive scale scores, as well as a series of exploratory structural equation modeling (ESEM) analyses to examine how these scales converged in multivariate latent space. Results generally showed empirical convergence between the scales of these two measures that were thematically meaningful and in accordance with conceptual expectations. Correlation analyses showed significant associations between conceptually expected scales, and the highest associations tended to be between scales that were theoretically related. ESEM analyses generated evidence for distinct internalizing, externalizing, and psychoticism factors across all analyses. These findings indicate convergence between these two measures and help further elucidate the associations between dysfunctional personality traits and general psychopathology.