Miriam K. Forbes

The Hierarchical Taxonomy of Psychopathology (HiTOP) : A Dimensional Alternative to Traditional Nosologies

The reliability and validity of traditional taxonomies are limited by arbitrary boundaries between psychopathology and normality, often unclear boundaries between disorders, frequent disorder co-occurrence, heterogeneity within disorders, and diagnostic instability. These taxonomies went beyond evidence available on the structure of psychopathology and were shaped by a variety of other considerations, which may explain the aforementioned shortcomings. The Hierarchical Taxonomy Of Psychopathology (HiTOP) model has emerged as a research effort to address these problems. It constructs psychopathological syndromes and their components/subtypes based on the observed covariation of symptoms, grouping related symptoms together and thus reducing heterogeneity. It also combines co-occurring syndromes into spectra, thereby mapping out comorbidity. Moreover, it characterizes these phenomena dimensionally, which addresses boundary problems and diagnostic instability. Here, we review the development of the HiTOP and the relevant evidence. The new classification already covers most forms of psychopathology. Dimensional measures have been developed to assess many of the identified components, syndromes, and spectra. Several domains of this model are ready for clinical and research applications. The HiTOP promises to improve research and clinical practice by addressing the aforementioned shortcomings of traditional nosologies. It also provides an effective way to summarize and convey information on risk factors, etiology, pathophysiology, phenomenology, illness course, and treatment response. This can greatly improve the utility of the diagnosis of mental disorders. The new classification remains a work in progress. However, it is developing rapidly and is poised to advance mental health research and care significantly as the relevant science matures.

Critical Flaws in the Female Sexual Function Index and the International Index of Erectile Function

The Female Sexual Function Index (FSFI; Rosen et al., 2000) and International Index of Erectile Function (IIEF; Rosen et al., 1997) are two of the most widely used measures of sexual dysfunction. However, they have potential measurement and psychometric flaws that have not been addressed in the literature. This article examines the measurement capabilities of these measures based on data collected from an online study in 2010. A convenience sample of 518 sexually active adults (65% female) drawn from the general community were included in the analyses. Both measures displayed critical theoretical and measurement problems for the assessment of sexual problems beyond sexual arousal, and for the sexual desire domains in particular. Based on these results, we encourage clinicians and researchers to think critically about whether the FSFI and IIEF are appropriate measures for their practice and research. In particular, these measures are inappropriate for use among individuals who are not currently sexually active, and research with a focus other than sexual arousal should consider supplementary measures of sexual function. The psychometric properties of these measures should be reassessed in clinical samples, but the theoretical issues with the measures raised in this article are relevant across clinical and research contexts.

Evidence that psychopathology symptom networks have limited replicability.

Network analysis is quickly gaining popularity in psychopathology research as a method that aims to reveal causal relationships among individual symptoms. To date, 4 main types of psychopathology networks have been proposed: (a) association networks, (b) regularized concentration networks, (c) relative importance networks, and (d) directed acyclic graphs. The authors examined the replicability of these analyses based on symptoms of major depression and generalized anxiety between and within 2 highly similar epidemiological samples (i.e., the National Comorbidity Survey—Replication [n = 9282] and the National Survey of Mental Health and Wellbeing [n = 8841]). Although association networks were stable, the 3 other types of network analysis (i.e., the conditional independence networks) had poor replicability between and within methods and samples. The detailed aspects of the models—such as the estimation of specific edges and the centrality of individual nodes—were particularly unstable. For example, 44% of the symptoms were estimated as the “most influential” on at least 1 centrality index across the 6 conditional independence networks in the full samples, and only 13–21% of the edges were consistently estimated across these networks. One of the likely reasons for the instability of the networks is the predominance of measurement error in the assessment of individual symptoms. The authors discuss the implications of these findings for the growing field of psychopathology network research, and conclude that novel results originating from psychopathology networks should be held to higher standards of evidence before they are ready for dissemination or implementation in the field.

Beyond comorbidity: Toward a dimensional and hierarchical approach to understanding psychopathology across the life span

We propose a novel developmentally informed framework to push research beyond a focus on comorbidity between discrete diagnostic categories and to move toward research based on the well-validated dimensional and hierarchical structure of psychopathology. For example, a large body of research speaks to the validity and utility of the internalizing and externalizing spectra as organizing constructs for research on common forms of psychopathology. The internalizing and externalizing spectra act as powerful explanatory variables that channel the psychopathological effects of genetic and environmental risk factors, predict adaptive functioning, and account for the likelihood of disorder-level manifestations of psychopathology. As such, our proposed theoretical framework uses the internalizing and externalizing spectra as central constructs to guide future psychopathology research across the life span. The framework is particularly flexible, because any of the facets or factors from the dimensional and hierarchical structure of psychopathology can form the focus of research. We describe the utility and strengths of this framework for developmental psychopathology in particular and explore avenues for future research.

The time has come for dimensional personality disorder diagnosis

Author(s): Hopwood, Christopher J; Kotov, Roman; Krueger, Robert F; Watson, David; Widiger, Thomas A; Althoff, Robert R; Ansell, Emily B; Bach, Bo; Michael Bagby, R; Blais, Mark A; Bornovalova, Marina A; Chmielewski, Michael; Cicero, David C; Conway, Christopher; De Clercq, Barbara; De Fruyt, Filip; Docherty, Anna R; Eaton, Nicholas R; Edens, John F; Forbes, Miriam K; Forbush, Kelsie T; Hengartner, Michael P; Ivanova, Masha Y; Leising, Daniel; John Livesley, W; Lukowitsky, Mark R; Lynam, Donald R; Markon, Kristian E; Miller, Joshua D; Morey, Leslie C; Mullins-Sweatt, Stephanie N; Hans Ormel, J; Patrick, Christopher J; Pincus, Aaron L; Ruggero, Camilo; Samuel, Douglas B; Sellbom, Martin; Slade, Tim; Tackett, Jennifer L; Thomas, Katherine M; Trull, Timothy J; Vachon, David D; Waldman, Irwin D; Waszczuk, Monika A; Waugh, Mark H; Wright, Aidan GC; Yalch, Mathew M; Zald, David H; Zimmermann, Johannes

Progress in achieving quantitative classification of psychopathology

Shortcomings of approaches to classifying psychopathology based on expert consensus have given rise to contemporary efforts to classify psychopathology quantitatively. In this paper, we review progress in achieving a quantitative and empirical classification of psychopathology. A substantial empirical literature indicates that psychopathology is generally more dimensional than categorical. When the discreteness versus continuity of psychopathology is treated as a research question, as opposed to being decided as a matter of tradition, the evidence clearly supports the hypothesis of continuity. In addition, a related body of literature shows how psychopathology dimensions can be arranged in a hierarchy, ranging from very broad “spectrum level” dimensions, to specific and narrow clusters of symptoms. In this way, a quantitative approach solves the “problem of comorbidity” by explicitly modeling patterns of co‐occurrence among signs and symptoms within a detailed and variegated hierarchy of dimensional concepts with direct clinical utility. Indeed, extensive evidence pertaining to the dimensional and hierarchical structure of psychopathology has led to the formation of the Hierarchical Taxonomy of Psychopathology (HiTOP) Consortium. This is a group of 70 investigators working together to study empirical classification of psychopathology. In this paper, we describe the aims and current foci of the HiTOP Consortium. These aims pertain to continued research on the empirical organization of psychopathology; the connection between personality and psychopathology; the utility of empirically based psychopathology constructs in both research and the clinic; and the development of novel and comprehensive models and corresponding assessment instruments for psychopathology constructs derived from an empirical approach.

Smoking, posttraumatic stress disorder, and alcohol use disorders in a nationally representative sample of Australian men and women

BACKGROUND Posttraumatic stress disorder (PTSD) and alcohol use disorders (AUDs) often co-occur with smoking and tobacco use disorders. Each of these disorders is known to have negative health consequences and impairment independently, but little is known about the impact of their co-occurrence. The aim of the present study is to examine the prevalence, correlates, order of onset, and impact of co-occurring daily smoking, PTSD, and AUDs. METHOD The 2007 Australian National Survey of Mental Health and Wellbeing (2007 NSMHWB) was a nationally representative survey of 8841 Australians. The survey assessed for 12-month DSM-IV mental disorders; the age respondents first started smoking daily, experienced a traumatic event, or developed problems with alcohol; and self-reported mental and physical health and impairment. RESULTS There were systematic patterns of co-occurrence between daily smoking, PTSD, and AUDs. Daily smoking and problems with alcohol use tended to develop after first trauma exposure, which is broadly consistent with the self-medication hypothesis. Daily smoking, PTSD, and AUDs were also associated with additive negative effects on mental and physical health and functioning, after controlling for demographics. CONCLUSIONS Smoking, PTSD, and AUDs commonly co-occur in this nationally representative sample of Australian men and women, and this comorbidity was associated with greater severity of mental and physical health problems and impairment in several areas of functioning. This study highlights the importance of identifying and eliminating these patterns of co-occurrence, potentially through integrated interventions.

A network approach to modeling comorbid internalizing and alcohol use disorders.

Internalizing disorders co-occur with alcohol use disorder (AUD) at a rate that exceeds chance and compromise conventional AUD treatment. The “vicious cycle” model of comorbidity specifies drinking to cope (DTC) as a link between these disorders that, when not directly addressed, undermines the effectiveness of conventional treatments. Interventions based on this model have proven successful but there is no direct evidence for how and to what extent DTC contributes to the maintenance of comorbidity. In the present study, we used network analysis to depict associations between syndrome-specific groupings of internalizing symptoms, alcohol craving, and drinking behavior, as well as DTC and other extradiagnostic variables specified in the vicious cycle model (e.g., perceived stress and coping self-efficacy). Network analyses of 362 individuals with comorbid anxiety and AUD assessed at the beginning of residential AUD treatment indicated that while internalizing conditions and drinking elements had only weak direct associations, they were strongly connected with DTC and perceived stress. Consistent with this, centrality indices showed that DTC ranked as the most central/important element in the network in terms of its “connectedness” to all other network elements. A series of model simulations—in which individual elements were statistically controlled for—demonstrated that DTC accounted for all the relationships between the drinking-related elements and internalizing elements in the network; no other variable had this effect. Taken together, our findings suggest that DTC may serve as a “keystone” process in maintaining comorbidity between internalizing disorders and AUD.

A Structural Equation Modeling Analysis of the Relationships between Depression, Anxiety, and Sexual Problems over Time

Sexual dysfunctions are related to depressive and anxiety disorders, but the nature of these relationships remains unclear. This study examined the relationship among symptoms of these disorders over time by comparing (a) a model that included causal relationships, (b) a model that accounted for change over time with a shared underlying factor (or latent liability) among all the disorders, and (c) a model that conceptualized sexual dysfunctions as unrelated to depressive and anxiety disorders over time. Participants (n = 1,012) completed online self-report measures of sexual dysfunctions and depressive and anxiety disorders across six time points at either weekly or monthly intervals. Models 1 and 2 provided equal best fit for men and women based on data collected four weeks apart, but there were no evident causal relationships in Model 1. Subsequent analyses using data collected one week and six months apart found Model 2 provided robust fit for women, but these data were not examined for men due to inadequate sample sizes. The results are consistent with a shared latent liability of internalizing psychopathology driving the change in these disorders over time, which provides a clear direction for an empirically driven nosology and for future research into transdiagnostic treatments.

Should Sexual Problems Be Included in the Internalizing Spectrum? A Comparison of Dimensional and Categorical Models

Preliminary research has suggested that sexual problems should be included in the internalizing spectrum alongside depressive and anxiety disorders. This study aimed to empirically examine and compare an extended internalizing spectrum model with a categorical framework model implied by the current nosological structure. Responses to an online survey from a community sample (n = 518) were analyzed to compare the fit of six alternative models of the relationship between sexual problems and depressive and anxiety disorders, separately for men and women. The best model for women (n = 336) was a dimensional spectrum model that included sexual arousal, orgasm, and pain difficulties in the internalizing spectrum. The results for men (n = 182) were less clear-cut: there were apparent categorical relationships for a small group (n = 8), and the spectrum model showed a good fit for 96% of the sample. These findings are consistent with a nosology that maintains discrete disorders and diagnostic chapters while recognizing the relationships between them, as in the new structure of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders. As such, this study offers further evidence that there are dimensional relationships between sexual problems and depressive and anxiety disorders, which should be explicitly recognized in diagnostic systems.