Efficiently measuring dimensions of the externalizing spectrum model: Development of the Externalizing Spectrum Inventory-Computerized Adaptive Test (ESI-CAT)

The development of the Externalizing Spectrum Inventory (ESI) was motivated by the need to comprehensively assess the interrelated nature of externalizing psychopathology and personality using an empirically driven framework. The ESI measures 23 theoretically distinct yet related unidimensional facets of externalizing, which are structured under 3 superordinate factors representing general externalizing, callous aggression, and substance abuse. One limitation of the ESI is its length at 415 items. To facilitate the use of the ESI in busy clinical and research settings, the current study sought to examine the efficiency and accuracy of a computerized adaptive version of the ESI. Data were collected over 3 waves and totaled 1,787 participants recruited from undergraduate psychology courses as well as male and female state prisons. A series of 6 algorithms with different termination rules were simulated to determine the efficiency and accuracy of each test under 3 different assumed distributions. Scores generated using an optimal adaptive algorithm evidenced high correlations (r > .9) with scores generated using the full ESI, brief ESI item-based factor scales, and the 23 facet scales. The adaptive algorithms for each facet administered a combined average of 115 items, a 72% decrease in comparison to the full ESI. Similarly, scores on the item-based factor scales of the ESI-brief form (57 items) were generated using on average of 17 items, a 70% decrease. The current study successfully demonstrates that an adaptive algorithm can generate similar scores for the ESI and the 3 item-based factor scales using a fraction of the total item pool. (PsycINFO Database Record

Reliability and clinical usefulness of the personality inventory for DSM-5 in clinically referred adolescents: A preliminary report in a sample of Italian inpatients

BACKGROUND

The DSM-5 Alternative Model of Personality Disorders (AMPD) provides the opportunity to integrate the needed developmental perspective in the assessment of personality pathology. Based on this model, Krueger and colleagues (2012) developed the Personality Inventory for DSM-5 (PID-5), which operationalizes the proposed DSM-5 traits.

METHODS

Eighty-five consecutively admitted Italian adolescent inpatients were administered the Italian translation of the PID-5, in order to obtain preliminary data on PID-5 reliability and clinical usefulness in clinically referred adolescents.

RESULTS

With the possible exception of the PID-5 Suspiciousness scale, all other PID-5 scales evidenced adequate internal consistency reliability (i.e., Cronbach's α values of at least .70, most being greater than .80). Our data seemed to yield at least partial support for the construct validity of the PID-5 scales also in clinical adolescents, at least in terms of patterns of associations with dimensionally assessed DSM-5 Section II PDs that were also included in the DSM-5 AMPD (excluding Antisocial PD because of the participants' minor age). Finally, our data suggested that the clinical usefulness of the PID-5 in adolescent inpatients may extend beyond PDs to profiling adolescents at risk for life-threatening suicide attempts. In particular, PID-5 Depressivity, Anhedonia, and Submissiveness trait scales were significantly associated with adolescents' history of life-threatening suicide attempts, even after controlling for a number of other variables, including mood disorder diagnosis.

DISCUSSION

As a whole, our study may provide interesting, albeit preliminary data as to the clinical usefulness of PID-5 in the assessment of adolescent inpatients.

Psychometric Properties of the Spanish PID-5 in a Clinical and a Community Sample

The Personality Inventory for DSM-5 (PID-5) measures the trait part (Criterion B) of the alternative model for personality disorders proposed in Section III of DSM-5. Although its psychometric properties have proven adequate thus far, evidence is limited in other languages and in clinical samples. The Spanish PID-5 was examined in two samples comprising 446 clinical and 1,036 community subjects. Facet scales showed good internal consistency in both samples (median α = .86 and .79) and were unidimensional under exploratory and confirmatory approaches. They were also able to distinguish between clinical and community subjects with a mean standardized difference of z = 0.81. All facets except for Risk Taking were unipolar, such that the upper poles indicated pathology and the lower poles reflected normality, rather than the opposite pole of abnormality. The entire PID-5 hierarchical structure, from one to five factors, was confirmed in both samples with Tucker's congruence coefficients over .95.

Understanding Psychopathology: Melding Behavior Genetics, Personality, and Quantitative Psychology to Develop an Empirically Based Model

Research on psychopathology is at a historical crossroads. New technologies offer the promise of lasting advances in our understanding of the causes of human psychological suffering. Making the best use of these technologies, however, requires an empirically accurate model of psychopathology. Much current research is framed by the model of psychopathology portrayed in current versions of the Diagnostic and Statistical Manual of Mental Disorders (DSM; American Psychiatric Association, 2000). Although the modern DSMs have been fundamental in advancing psychopathology research, recent research also challenges some assumptions made in the DSM-for example, the assumption that all forms of psychopathology are well conceived of as discrete categories. Psychological science has a critical role to play in working through the implications of this research and the challenges it presents. In particular, behavior-genetic, personality, and quantitative-psychological research perspectives can be melded to inform the development of an empirically based model of psychopathology that would constitute an evolution of the DSM.

Optimizing efficiency of psychopathology assessment through quantitative modeling: development of a brief form of the Externalizing Spectrum Inventory

The Externalizing Spectrum Inventory (ESI; Krueger, Markon, Patrick, Benning, & Kramer, 2007) provides for integrated, hierarchical assessment of a broad range of problem behaviors and traits in the domain of deficient impulse control. The ESI assesses traits and problems in this domain through 23 lower order facet scales organized around 3 higher order dimensions, reflecting general disinhibition, callous aggression, and substance abuse. The full-form ESI contains 415 items, and a shorter form would be useful for questionnaire screening studies or multimethod research protocols. In the current work, we employed item response theory and structural modeling methods to create a 160-item brief form (ESI-BF) that provides for efficient measurement of the ESI's lower order facets and quantification of its higher order dimensions either as scale-based factors or as item-based composites. The ESI-BF is recommended for use in research on psychological or neurobiological correlates of problems such as risk-taking, delinquency, aggression, and substance abuse, and studies of general and specific mechanisms that give rise to problems of these kinds.

A Head-to-Head Comparison of the Personality Inventory for DSM-5 (PID-5) With the Personality Diagnostic Questionnaire-4 (PDQ-4) in Predicting the General Level of Personality Pathology Among Community Dwelling Subjects

In order to evaluate if measures of DSM-5 Alternative PD Model domains predicted interview-based scores of general personality pathology when compared to self-report measures of DSM-IV Axis II/DSM-5 Section II PD criteria, 300 Italian community adults were administered the Iowa Personality Disorder Screen (IPDS) interview, the Personality Inventory for DSM-5 (PID-5), and the Personality Diagnostic Questionnaire-4+ (PDQ-4+). Multiple regression analyses showed that the five PID-5 domain scales collectively explained an adequate rate of the variance of the IPDS interview total score. This result was slightly lower than the amount of variance in the IPDS total score explained by the 10 PDQ-4+ scales. The PID-5 traits scales performed better than the PDQ-4+, although the difference was marginal. Hierarchical regression analyses revealed that the PID-5 domain and trait scales provided a moderate, but significant increase in the prediction of the general level of personality pathology above and beyond the PDQ-4+ scales.

The Personality Inventory for DSM-5 Brief Form: Evidence for Reliability and Construct Validity in a Sample of Community-Dwelling Italian Adolescents

To assess the reliability and construct validity of the Personality Inventory for DSM-5 Brief Form (PID-5-BF) among adolescents, 877 Italian high school students were administered the PID-5-BF. Participants were administered also the Measure of Disordered Personality Functioning (MDPF) as a criterion measure. In the full sample, Cronbach's alpha values for the PID-5-BF scales ranged from .59 (Detachment) to .77 (Psychoticism); in addition, all PID-5-BF scales showed mean interitem correlation values in the .22 to .40 range. Cronbach's alpha values for the PID-5-BF total score was .83 (mean interitem r = .16). Although 2-month test-retest reliability could be assessed only in a small ( n = 42) subsample of participants, all PID-5-BF scale scores showed adequate temporal stability, as indexed by intraclass r values ranging from .78 (Negative Affectivity) to .97 (Detachment), all ps <.001. Exploratory structural equation modeling analyses provided at least moderate support for the a priori model of PID-5-BF items. Multiple regression analyses showed that PID-5-BF scales predicted a nonnegligible amount of variance in MDPF Non-Cooperativeness, adjusted R² = .17, p < .001, and Non-Coping scales, adjusted R² = .32, p < .001. Similarly, the PID-5-BF total score was a significant predictor of both MDPF Non-Coping, and Non-Cooperativeness scales.

A descriptivist approach to trait conceptualization and inference

In their recent article, How Functionalist and Process Approaches to Behavior Can Explain Trait Covariation, Wood, Gardner, and Harms (2015) underscore the need for more process-based understandings of individual differences. At the same time, the article illustrates a common error in the use and interpretation of latent variable models: namely, the misuse of models to arbitrate issues of causation and the nature of latent variables. Here, we explain how latent variables can be understood simply as parsimonious summaries of data, and how statistical inference can be based on choosing those summaries that minimize information required to represent the data using the model. Although Wood, Gardner, and Harms acknowledge this perspective, they underestimate its significance, including its importance to modeling and the conceptualization of psychological measurement. We believe this perspective has important implications for understanding individual differences in a number of domains, including current debates surrounding the role of formative versus reflective latent variables.

Eudaimonic well-being and tumor norepinephrine in patients with epithelial ovarian cancer

BACKGROUND

The impact of psychological well-being on the physiologic processes involved in cancer progression remains unclear. Prior research has implicated adrenergic signaling in tumor growth and metastasis. Given that adrenergic signaling is influenced by both positive and negative factors, the authors examined how 2 different aspects of well-being (eudaimonic and positive affect) and psychological distress were associated with tumor norepinephrine (NE) in patients with ovarian cancer.

METHODS

A total of 365 women with suspected ovarian cancer completed psychosocial assessments before surgery and clinical information was obtained from medical records. Study inclusion was confirmed after histological diagnosis. Tumor NE was measured in frozen tissue samples using high-performance liquid chromatography with electrochemical detection. Confirmatory factor analysis was used to model eudaimonic well-being, positive affect, and psychological distress, and structural equation modeling was used to examine associations between these factors and tumor NE.

RESULTS

Eudaimonic well-being, positive affect, and psychological distress, modeled as distinct but correlated constructs, best fit the data (ie, compared with unitary or 2-factor models) (root mean square error of approximation, 0.048; comparative fit index, 0.982; and standardized root-mean-squared residual, 0.035). Structural equation modeling analysis that included physical well-being, stage of disease, histology, psychological treatment history, beta-blocker use, and caffeine use as covariates was found to have good model fit (root mean square error of approximation, 0.052; comparative fit index, 0.955; and standardized root-mean-squared residual, 0.036) and demonstrated that eudaimonic well-being was related to lower tumor NE (β = -.24 [P = .045]). In contrast, no effects were found for positive affect or psychological distress.

CONCLUSIONS

Eudaimonic well-being was found to be associated with lower tumor NE, independent of positive affect and psychological distress. Because adrenergic signaling is implicated in tumor progression, increasing eudaimonic well-being may improve both psychological and physiologic resilience in patients with ovarian cancer.

Adaptive and maladaptive personality traits in high-risk gamblers

Gambling Disorder (GD) is an addictive disorder resulting in significant impairment in occupational and social functioning. The aim of the present study was to investigate the relationship of GD risk to adaptive and maladaptive personality dimensions in a sample of nonreferred Italian gamblers. The authors found the risk for GD to show significant associations with the Openness and Conscientiousness scales of the Big Five Inventory (BFI); however, these effects were not significant after controlling for alcohol and drug use. GD risk showed significant associations with the Detachment and Antagonism domains of the Personality Inventory for DSM-5 (PID-5), as well as with the PID-5 facet scales of Hostility, Callousness, Deceitfulness, Manipulativeness, Irresponsibility, and (low) Rigid Perfectionism, even when controlling for alcohol and drug use. Maladaptive personality dispositions may serve as risk factors for pathological gambling, even beyond their impact on frequently concomitant problems with alcohol and other drugs.

Testing whether the DSM-5 personality disorder trait model can be measured with a reduced set of items: An item response theory investigation of the Personality Inventory for DSM-5

The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) includes an alternative model of personality disorders (PDs) in Section III, consisting in part of a pathological personality trait model. To date, the 220-item Personality Inventory for DSM-5 (PID-5; Krueger, Derringer, Markon, Watson, & Skodol, 2012) is the only extant self-report instrument explicitly developed to measure this pathological trait model. The present study used item response theory-based analyses in a large sample (n = 1,417) to investigate whether a reduced set of 100 items could be identified from the PID-5 that could measure the 25 traits and 5 domains. This reduced set of PID-5 items was then tested in a community sample of adults currently receiving psychological treatment (n = 109). Across a wide range of criterion variables including NEO PI-R domains and facets, DSM-5 Section II PD scores, and externalizing and internalizing outcomes, the correlational profiles of the original and reduced versions of the PID-5 were nearly identical (rICC = .995). These results provide strong support for the hypothesis that an abbreviated set of PID-5 items can be used to reliably, validly, and efficiently assess these personality disorder traits. The ability to assess the DSM-5 Section III traits using only 100 items has important implications in that it suggests these traits could still be measured in settings in which assessment-related resources (e.g., time, compensation) are limited.

A Head-to-Head Comparison of the Personality Inventory for DSM-5 (PID-5) With the Personality Diagnostic Questionnaire-4 (PDQ-4) in Predicting the General Level of Personality Pathology Among Community Dwelling Subjects

In order to evaluate if measures of DSM-5 Alternative PD Model domains predicted interview-based scores of general personality pathology when compared to self-report measures of DSM-IV Axis II/DSM-5 Section II PD criteria, 300 Italian community adults were administered the Iowa Personality Disorder Screen (IPDS) interview, the Personality Inventory for DSM-5 (PID-5), and the Personality Diagnostic Questionnaire-4+ (PDQ-4+). Multiple regression analyses showed that the five PID-5 domain scales collectively explained an adequate rate of the variance of the IPDS interview total score. This result was slightly lower than the amount of variance in the IPDS total score explained by the 10 PDQ-4+ scales. The PID-5 traits scales performed better than the PDQ-4+, although the difference was marginal. Hierarchical regression analyses revealed that the PID-5 domain and trait scales provided a moderate, but significant increase in the prediction of the general level of personality pathology above and beyond the PDQ-4+ scales.

Challenges and strategies in helping the DSM become more dimensional and empirically based

The DSM-5 creation process and outcome underlines a core tension in psychiatry between empirical evidence that mental pathologies tend to be dimensional and a historical emphasis on delineating categorical disorders to frame psychiatric thinking. The DSM has been slow to reflect dimensional evidence because doing so is often perceived as a disruptive paradigm shift. As a result, other authorities are making this shift, circumventing the DSM in the process. For example, through the Research Domain Criteria (RDoC), NIMH now encourages investigators to focus on a dimensional and neuroscientific conceptualization of mental disorder research. Fortunately, the DSM-5 contains a dimensional model of maladaptive personality traits that provides clinical descriptors that align conceptually with the neuroscience-based dimensions delineated in the RDoC and in basic science research. Through frameworks such as the DSM-5 trait model, the DSM can evolve to better incorporate evidence of the dimensionality of mental disorder.

ADHD and the externalizing spectrum: direct comparison of categorical, continuous, and hybrid models of liability in a nationally representative sample

PURPOSE

Alcohol use disorders, substance use disorders, and antisocial personality disorder share a common externalizing liability, which may also include attention-deficit hyperactivity disorder (ADHD). However, few studies have compared formal quantitative models of externalizing liability, with the aim of delineating the categorical and/or continuous nature of this liability in the community. This study compares categorical, continuous, and hybrid models of externalizing liability.

METHOD

Data were derived from the 2004-2005 National Epidemiologic Survey on Alcohol and Related Conditions (N = 34,653). Seven disorders were modeled: childhood ADHD and lifetime diagnoses of antisocial personality disorder (ASPD), nicotine dependence, alcohol dependence, marijuana dependence, cocaine dependence, and other substance dependence.

RESULTS

The continuous latent trait model provided the best fit to the data. Measurement invariance analyses supported the fit of the model across genders, with females displaying a significantly lower probability of experiencing externalizing disorders. Cocaine dependence, marijuana dependence, other substance dependence, alcohol dependence, ASPD, nicotine dependence, and ADHD provided the greatest information, respectively, about the underlying externalizing continuum.

CONCLUSIONS

Liability to externalizing disorders is continuous and dimensional in severity. The findings have important implications for the organizational structure of externalizing psychopathology in psychiatric nomenclatures.

The structure and correlates of self-reported DSM-5 maladaptive personality traits: findings from two German-speaking samples

The authors investigated the structure and correlates of DSM-5 maladaptive personality traits in two samples of 577 students and 212 inpatients using the German self-report form of the Personality Inventory for DSM-5. They found that (a) the factor structure of DSM-5 trait facets is largely in line with the proposed trait domains of Negative Affectivity, Detachment, Antagonism, Disinhibition, and Psychoticism; (b) all DSM-5 trait domains except Psychoticism are highly related to the respective domains of the Five-Factor Model of personality; (c) the trait facets are positively associated with a self-report measure of general personality dysfunction; and (d) the DSM-5 trait facets show differential associations with a range of self-reported DSM-IV Axis I disorders. These findings give further support to the new DSM-5 trait model and suggest that it may generalize to other languages and cultures.

Characteristics and stability of empirically derived anorexia nervosa subtypes: towards the identification of homogeneous low-weight eating disorder phenotypes

Anorexia nervosa (AN) is characterized by within-group heterogeneity in symptom presentation, which poses problems for research on etiology and treatment. This study sought to identify homogeneous subtypes of AN, and examine their short-term stability, using empirical methods. A treatment-seeking sample with AN (n = 194) was assessed at baseline and 6- and 12-month follow-ups. Latent class analysis was used to identify homogeneous AN subgroups, and latent transition analysis was used to examine the stability of latent classes. Three low-weight eating disorder classes were identified: 1) fat-phobic restricting (AN-R-FP); 2) fat-phobic binge-eating/purging (AN-BP-FP); and 3) non-fat-phobic restricting (AN-R-NFP). Subtype membership was stable over follow-up, with .68 to .88 probabilities of remaining in the same class from baseline to 6 months, and .87 to 1.00 from 6 months to 12 months. The most common transition pattern was between AN-R-FP and AN-R-NFP (56.8% of transitions); the majority of these participants transitioned from AN-R-FP to AN-R-NFP (n = 20/21). Predictors of latent class membership included lifetime mood and substance use disorder comorbidities, negative temperament, illness duration, and body mass index at treatment presentation. Disinhibition (vs. constraint), history of overweight or obesity, and illness duration decreased the probability of latent transition. Findings support the presence of 3 low-weight eating disorder phenotypes that are highly stable over short-term follow-up. Identification of a stable non-fat-phobic AN phenotype is intriguing and highlights the importance of studying mechanisms that differentiate fat-phobic and non-fat-phobic eating disorders.

A meta-analytic evaluation of the endophenotype hypothesis: effects of measurement paradigm in the psychiatric genetics of impulsivity

Recent transitions in psychiatric nosology have stimulated discussion about what constructs and what level of analysis are most appropriate for the study of psychopathology. The endophenotype hypothesis suggests that neurobiological and neuropsychological phenotypes will be superior to trait or diagnostic measures in elucidating the substrates of psychopathology, as the former are more proximal, and therefore more sensitive, to underlying etiology. This meta-analysis explores these issues by comparing the magnitude of genetic effects associated with phenotypes at different levels of analysis. Studies of 3 common polymorphisms-the short and long variants of the serotonin-transporter-linked polymorphic region (5-HTTLPR), the variable number tandem repeat polymorphism in the 3' untranslated region of the dopamine active transporter gene (DAT1 3' UTR VNTR), and the 48 base-pair VNTR in exon-3 of the dopamine D4 receptor gene (DRD4)-and their effects on phenotypes of impulsivity were examined. Consistent with endophenotype theory, level of phenotype moderated the magnitude of genetic effects. Diagnostic, trait and neuropsychological, then neurobiological phenotypes yielded successively larger effects. However, consistent with emerging meta-analytic findings, neurobiological phenotypes were most susceptible to bias and inflation, raising questions about the validity of reported effects.

The role of the DSM-5 personality trait model in moving toward a quantitative and empirically based approach to classifying personality and psychopathology

The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) represents a watershed moment in the history of official psychopathology classification systems because it is the first DSM to feature an empirically based model of maladaptive personality traits. Attributes of patients with personality disorders were discussed by the DSM-5 Personality and Personality Disorders Work Group and then operationalized and refined in the course of an empirical project that eventuated in the construction of the Personality Inventory for DSM-5 (PID-5). We review research to date on the DSM-5 trait model, with a primary aim of discussing how this kind of research could serve to better tether the DSM to data as it continues to evolve. For example, studies to date suggest that the DSM-5 trait model provides reasonable coverage of personality pathology but also suggest areas for continued refinement. This kind of research provides a way of evolving psychopathology classification on the basis of research evidence as opposed to clinical authority.

Toward a theory of distinct types of "impulsive" behaviors: A meta-analysis of self-report and behavioral measures

Impulsivity is considered a personality trait affecting behavior in many life domains, from recreational activities to important decision making. When extreme, it is associated with mental health problems, such as substance use disorders, as well as with interpersonal and social difficulties, including juvenile delinquency and criminality. Yet, trait impulsivity may not be a unitary construct. We review commonly used self-report measures of personality trait impulsivity and related constructs (e.g., sensation seeking), plus the opposite pole, control or constraint. A meta-analytic principal-components factor analysis demonstrated that these scales comprise 3 distinct factors, each of which aligns with a broad, higher order personality factor-Neuroticism/Negative Emotionality, Disinhibition versus Constraint/Conscientiousness, and Extraversion/Positive Emotionality/Sensation Seeking. Moreover, Disinhibition versus Constraint/Conscientiousness comprise 2 correlated but distinct subfactors: Disinhibition versus Constraint and Conscientiousness/Will versus Resourcelessness. We also review laboratory tasks that purport to measure a construct similar to trait impulsivity. A meta-analytic principal-components factor analysis demonstrated that these tasks constitute 4 factors (Inattention, Inhibition, Impulsive Decision-Making, and Shifting). Although relations between these 2 measurement models are consistently low to very low, relations between both trait scales and laboratory behavioral tasks and daily-life impulsive behaviors are moderate. That is, both independently predict problematic daily-life impulsive behaviors, such as substance use, gambling, and delinquency; their joint use has incremental predictive power over the use of either type of measure alone and furthers our understanding of these important, problematic behaviors. Future use of confirmatory methods should help to ascertain with greater precision the number of and relations between impulsivity-related components.

Epistemological pluralism and scientific development: an argument against authoritative nosologies

The author examines the influence of authoritative nosological systems--those developed by an authoritative body or organization (e.g., the DSM, ICD, RDoC)--on the development of scientific theory and research. Although there has been extensive discussion of how such systems should be organized, and of the historical role of such systems, little focus has been placed on whether these systems impede or facilitate scientific progress. The author reviews the nature and role of constructs in scientific theory and the role of authoritative taxonomy in science. He presents an argument that, although authoritative classification systems clearly have value for nonscientific purposes, or for specific scientific purposes, the systems themselves, at least as they have been constructed thus far, likely impede scientific development by constraining competitive discourse. Implications and recommendations are discussed.

Reliability and Validity of the Personality Inventory for DSM-5 (PID-5)

In order to assess the internal consistency, factor structure, and ability to recover DSM-IV personality disorders (PDs) of the Personality Inventory for DSM-5 (PID-5) scales, 710 Italian adult community dwelling volunteers were administered the Italian translation of the PID-5, as well as the Italian translation of the Personality Diagnostic Questionnaire–4+ (PDQ-4+). Cronbach’s alpha values were >.70 for all PID-5 facet scales and greater than .90 for all PID-5 domain scales. Parallel analysis and confirmatory factor analysis supported the theoretical five-factor model of the PID-5 trait scales. Regression analyses showed that both PID-5 trait and domain scales explained a substantial amount of variance in the PDQ-4+ PD scales, with the exception of the Passive-Aggressive PD scale. When the PID-5 was administered to a second independent sample of 389 Italian adult community dwelling volunteers, the basic psychometric properties of the scale were replicated. In this second sample, the PID-5 trait and domain scales proved to be significant predictors of psychopathy measures. As a whole, the results of the present study support the hypothesis that the PID-5 is a reliable instrument which is able to recover DSM-IV PDs, as well as to capture personality pathology that is not included in the DSM-IV (namely, psychopathy).

A model of psychosis and its relationship with impairment

PURPOSE

Some studies suggest that positive symptoms of psychosis-clinical and sub-clinical alike-reflect a single, continuously distributed dimension in the population. It is unknown, however, whether such a spectrum of positive psychotic experiences is non-linearly related to outcomes such as daily functioning. This work aims to characterize the relationship between positive psychosis and impairment.

METHODS

Data from the Office of National Statistics National Psychiatric Morbidity Surveys of Great Britain were used to establish measurement models of psychosis and impairment. Competing linear and nonlinear models of the relationship between the two latent variables were evaluated using mixture structural equation models.

RESULTS

Positive psychosis is best modeled by a continuous, normal distribution. Increases in positive psychosis correlate with roughly linear increases in impairment.

CONCLUSIONS

Positive psychotic symptoms occur throughout the population without a discrete, pathological threshold. Functional deficits are linearly associated with the psychosis at all points along the continuum, and a significant portion of the population experiences subclinical psychosis.

How specific are the relationships between eating disorder behaviors and perfectionism?

Perfectionism is associated with several mental disorders, including depression, anxiety, and eating disorders. The goal of this study was to test the specificity of the associations between perfectionism facets and eating disorder behaviors, by examining whether neuroticism and conscientiousness mediated or moderated associations between these variables. Participants from a representative community sample (N = 407; 47% female) completed questionnaires assessing perfectionism, neuroticism, conscientiousness, and eating disorder behaviors. Neuroticism partially mediated associations between binge eating, restraint, body dissatisfaction, and maladaptive perfectionism facets. Neuroticism did not mediate associations between restriction and achievement striving perfectionism facets. Conscientiousness did not mediate any associations between perfectionism facets and eating disorder behaviors, yet Doubts about Actions interacted with conscientiousness to predict body dissatisfaction. Results indicate that neuroticism is key for understanding general risk factors that lead to myriad internalizing disorders, whereas maladaptive perfectionism has limited usefulness as a specific risk factor for eating disorder behaviors. Nevertheless, there is a unique association between dietary restraint and achievement striving dimensions of perfectionism that cannot be explained by higher-order personality traits.