Translating the Transdiagnostic: Aligning Assessment Practices With Research Advances

Researchers and clinicians working within the Diagnostic and Statistical Manual of Mental Disorders: Fifth Edition, Text Rev (DSM-5-TR) framework face a difficult question: what does it mean to have an evidence-based assessment of a nonevidence-based diagnostic construct? Alternative nosological approaches conceptualize psychopathology as (a) hierarchical, allowing researchers to move between levels of description and (b) dimensional, eliminating artificial dichotomies between disorders and the dichotomy between mental illness and mental well-being. In this article, we provide an overview of ongoing efforts to develop validated measures of transdiagnostic nosologies (i.e., the Hierarchical Taxonomy of Psychopathology; HiTOP) with applications for measurement-based care. However, descriptive models like HiTOP, which summarize patterns of covariation among psychopathology symptoms, do not address dynamic processes underlying the problems associated with psychopathology. Ambulatory assessment, well-suited to examine such dynamic processes, has also developed rapidly in recent decades. Thus, the goal of the current article is twofold. First, we provide a brief overview of developments in constructing valid measures of the HiTOP model as well as developments in ambulatory assessment practices. Second, we outline how these parallel developments can be integrated to advance measurement-based treatment. We end with a discussion of some major challenges for future research to address to integrate advances more fully in transdiagnostic and ambulatory assessment practices.

Operational definitions and measurement of externalizing behavior problems: An integrative review including research models and clinical diagnostic systems

Measurement of externalizing disorders such as antisocial disorders, attention-deficit/hyperactivity disorder or borderline disorder have relevant implications for the daily lives of people with these disorders. While the Diagnostic and Statistical Manual of Mental Disorders (DSM) and the International Classification of Diseases (ICD) have provided the diagnostic framework for decades, recent dimensional frameworks question the categorical approach of psychopathology, inherent in traditional nosotaxies. Tests and instruments develop under the DSM or ICD framework preferentially adopt this categorical approach, providing diagnostic labels. In contrast, dimensional measurement instruments provide an individualized profile for the domains that comprise the externalizing spectrum, but are less widely used in practice. Current paper aims to review the operational definitions of externalizing disorders defined under these different frameworks, revise the different measurement alternatives existing, and provide an integrative operational definition. First, an analysis of the operational definition of externalizing disorders among the DSM/ICD diagnostic systems and the recent Hierarchical Taxonomy of Psychopathology (HiTOP) model is carried out. Then, in order to analyze the coverage of operational definitions found, a description of measurement instruments among each conceptualization is provided. Three phases in the development of the ICD and DSM diagnosis systems can be observed with direct implications for measurement. ICD and DSM versions have progressively introduced systematicity, providing more detailed descriptions of diagnostic criteria and categories that ease the measurement instrument development. However, it is questioned whether the DSM/ICD systems adequately modelize externalizing disorders, and therefore their measurement. More recent theoretical approaches, such as the HiTOP model seek to overcome some of the criticism raised towards the classification systems. Nevertheless, several issues concerning this model raise mesasurement challenges. A revision of the instruments underneath each approach shows incomplete coverage of externalizing disorders among the existing instruments. Efforts to bring nosotaxies together with other theoretical models of psychopathology and personality are still needed. The integrative operational definition of externalizing disorders provided may help to gather clinical practice and research.

An Initial Investigation of the Joint Classification of Hypomania- and Neurodevelopmental Disorder-Relevant Dimensions Within the Hierarchical Taxonomy of Psychopathology

We examined hierarchical structural models of psychopathology in samples of (a) adults recruited online and screened based on psychopathology history (N = 429) and (b) undergraduates (N = 529) to inform classification of neurodevelopmental disorder (NDD)- and hypomania-relevant dimensions within the Hierarchical Taxonomy of Psychopathology (HiTOP). Results differed across samples in some ways, but converged to indicate that some NDD- and hypomania-relevant dimensions aligned closely with different HiTOP spectra. For example, some hypomania-relevant dimensions (e.g., affective lability) overlapped strongly with the internalizing spectrum, whereas others (e.g., self-perceived charisma) were reverse-indicators of detachment. Examination of cross-sectional and prospective correlates for emergent factors also was informative in some ways. This included NDD-relevant and disinhibited externalizing dimensions associating robustly with treatment seeking history and recent experiences of distress. These results provide initial insights into classifying NDD- and hypomania-relevant dimensions within the HiTOP and indicate a need for future research in this area.

Toward Precision Characterization and Treatment of Psychopathology: A Path Forward and Integrative Framework of the Hierarchical Taxonomy of Psychopathology and the Research Domain Criteria

A critical mission of psychological science is to conduct research that ultimately improves the lives of individuals who experience psychopathology. One important aspect of accomplishing this mission is increasing the likelihood that treatments will work for each person. I contend that treatment prognosis can be improved by moving toward a precision-medicine model. I advance a principle-driven framework for working toward these objectives. First, I synthesize the Hierarchical Taxonomy of Psychopathology and the Research Domain Criteria and demonstrate how integrating these models facilitates precision characterization of psychopathology. Second, I outline and demonstrate a systematic process for approaching treatment selection by leveraging precisely characterized representations of psychopathology. Finally, I advocate the research and clinical applications of this framework. Although clinical and psychological scientists are conducting exciting, multidisciplinary, and methodologically rigorous research in their respective domains, the impact of these pursuits will be maximized in the context of a unifying theoretical framework that supports a clear guiding mission.

A Hierarchical Taxonomy of Psychopathology (HiTOP) Primer for Mental Health Researchers

Mental health research is at an important crossroads as the field seeks more reliable and valid phenotypes to study. Dimensional approaches to quantifying mental illness operate outside the confines of traditional categorical diagnoses, and they are gaining traction as a way to advance research on the causes and consequences of mental illness. The Hierarchical Taxonomy of Psychopathology (HiTOP) is a leading dimensional research paradigm that synthesizes decades of data on the major dimensions of psychological disorders. In this article, we demonstrate how to use the HiTOP model to formulate and test research questions through a series of tutorials. To boost accessibility, data and annotated code for each tutorial are included at OSF (https://osf.io/8myzw). After presenting the tutorials, we outline how investigators can use these ideas and tools to generate new insights in their own substantive research programs.

Klerman's "credo" reconsidered: neo-Kraepelinianism, Spitzer's views, and what we can learn from the past

In 1978, G. Klerman published an essay in which he named the then-nascent "neo-Kraepelinian" movement and formulated a "credo" of nine propositions expressing the movement's essential claims and aspirations. Klerman's essay appeared on the eve of the triumph of neo-Kraepelinian ideas in the DSM-III. However, this diagnostic system has subsequently come under attack, opening the way for competing proposals for the future of psychiatric nosology. To better understand what is at stake, in this paper I provide a close reading and consideration of Klerman's credo in light of the past forty years of research and reflection. The credo is placed in the context of two equally seminal publications in the same year, one by S. Guze, the leading neo-Kraepelinian theorist, and the other by R. Spitzer and J. Endicott, defining mental disorder. The divergences between Spitzer and standard neo-Kraepelinianism are highlighted and argued to be much more important than is generally realized. The analysis of Klerman's credo is also argued to have implications for how to satisfactorily resolve the current nosological ferment in psychiatry. In addition to issues such as creating descriptive syndromal diagnostic criteria, overthrowing psychoanalytic dominance of psychiatry, and making psychiatry more scientific, neo-Kraepelinians were deeply concerned with the conceptual issue of the nature of mental disorder and the defense of psychiatry's medical legitimacy in response to antipsychiatric criticisms. These issues cannot be ignored, and I argue that proposals currently on offer to replace the neo-Kraepelinian system, especially popular proposals to replace it with dimensional measures, fail to adequately address them.

Neurobiology and the Hierarchical Taxonomy of Psychopathology: progress toward ontogenetically informed and clinically useful nosology

The Hierarchical Taxonomy of Psychopathology (HiTOP) is an empirical structural model of psychological symptoms formulated to improve the reliability and validity of clinical assessment. Neurobiology can inform assessments of early risk and intervention strategies, and the HiTOP model has greater potential to interface with neurobiological measures than traditional categorical diagnoses given its enhanced reliability. However, one complication is that observed biological correlates of clinical symptoms can reflect various factors, ranging from dispositional risk to consequences of psychopathology. In this paper, we argue that the HiTOP model provides an optimized framework for conducting research on the biological correlates of psychopathology from an ontogenetic perspective that distinguishes among indicators of liability, current symptoms, and consequences of illness. Through this approach, neurobiological research can contribute more effectively to identifying individuals at high dispositional risk, indexing treatment-related gains, and monitoring the consequences of mental illness, consistent with the aims of the HiTOP framework.


Developing Preliminary Scales for Assessing the HiTOP Detachment Spectrum

The Hierarchical Taxonomy of Psychopathology (HiTOP) is an empirical-based classification of psychopathology. Detachment is one of the six spectra in the current HiTOP working model. The aim of this study was to develop preliminary scales for the HiTOP Detachment spectrum that can be used in the next phase of developing a comprehensive measure of HiTOP. We had 456 participants from MTurk (Sample 1) and 266 university students (Sample 2) complete an online survey including a pool of 247 Detachment items assessing 15 consensually defined low-order constructs. Using a stepwise procedure involving factor analyses and ant colony optimization methods, we developed seven 8-item scales that capture unipolar facets of Detachment: anhedonia, suspiciousness, social withdrawal, intimacy avoidance, unassertiveness, risk aversion, and restricted affectivity. Three other 8-item scales emerged that tapped into a Maladaptive Extraversion construct (attention-seeking, thrill-seeking, and domineering), which was mostly unrelated to unipolar Detachment in factor analyses. The 10 scales were unidimensional, reliable, and showed some evidence of convergent and discriminant validity. We discuss challenges of assessing Detachment when moving forward with developing a comprehensive measure of HiTOP.

Distinguishing Transdiagnostic versus Disorder-Specific Pathways between Ruminative Brooding and Internalizing Psychopathology in Adolescents: A Latent Variable Modeling Approach

Rumination is correlated with diverse types of internalizing problems, but the extent to which it relates to a higher-order internalizing spectrum versus disorder-specific pathology is unclear. Using a quantitative model of the internalizing dimension, we compared the strength of transdiagnostic versus diagnosis-specific pathways from brooding-the most depressogenic component of rumination-to major depressive disorder (MDD) in adolescents. Community-recruited mid-adolescents (N = 241, M_age = 15.90 years, 53% female) completed semi-structured interviews of anxiety and depressive conditions and a self-report brooding measure. Confirmatory factor analysis revealed good fit for a one-factor model of internalizing conditions. Results revealed a large, significant factor correlation between brooding and the internalizing factor (r = 0.55), with some evidence for a more modest specific link between brooding and the unique component of the MDD diagnosis (r = 0.17; approximately one-third as large as the transdiagnostic pathway). These cross-sectional associations were generally consistent across two assessment waves separated by 19 months. We concluded that brooding is better conceptualized as a common characteristic of all internalizing problems in adolescence, rather than a specific feature of MDD. Preregistered hypotheses, data analysis code, and correlation matrices for this study are posted at https://osf.io/dax7u/ .

Beyond Distress and Fear: Differential Psychopathology Correlates of PTSD Symptom Clusters

BACKGROUND

Research suggests that re-experiencing and avoidance are "core" PTSD symptoms, but there has been little research explicating their unique connections to psychopathology other than internalizing conditions such as depression and anxiety. We aim to unpack symptom heterogeneity within PTSD by exploring associations between re-experiencing and avoidance clusters and major psychopathology domains in a dimensional metastructural framework (e.g., the Hierarchical Taxonomy of Psychopathology, or HiTOP).

METHOD

We used a trauma-exposed community sample (n = 233, 66.1% female, mean age = 45 years) to compare re-experiencing and avoidance's associations with factor-analytically derived dimensions generally corresponding to HiTOP structure: Distress, Fear, Detachment, Antagonism, Disinhibition, Thought Disorder, and Compulsivity.

RESULTS

Both re-experiencing and avoidance were robustly related to Fear. Re-experiencing was particularly related to Distress and Thought Disorder, whereas avoidance was related to domains involving overinhibition (e.g., Compulsivity). Relative to avoidance, re-experiencing had broader and more substantial associations with psychopathology, partly as a function of its greater saturation with dysphoria.

LIMITATIONS

Coverage of PTSD symptoms was limited to questionnaire measurement of re-experiencing and avoidance clusters. Results need to be replicated in samples selected for posttraumatic psychopathology.

CONCLUSION

Although they are strongly intercorrelated and both are robustly related to Fear, re-experiencing and avoidance differ substantially in their unique relations with other forms of psychopathology, and re-experiencing may be less specific to PTSD than previously thought. These differences can be used to understand the etiology and phenomenology of re-experiencing and avoidance in greater depth to inform more targeted and effective interventions for posttraumatic psychopathology.

A Population-Based Examination of Criterion-Level Disparities in the Diagnosis of Borderline Personality Disorder Among Sexual Minority Adults

Sexual minority individuals are diagnosed with borderline personality disorder (BPD) at higher proportions than heterosexual individuals regardless of presenting psychopathology. It is unclear if such bias is reflective of diagnostician idiosyncrasies or population-based diagnostic/criterion bias. Data from the National Epidemiologic Survey on Alcohol and Related Conditions-III were utilized to examine if differences in BPD endorsement were related to/independent of transdiagnostic factor differences between sexual minority and heterosexual individuals. BPD diagnosis/criterion endorsement was higher among sexual minority compared with heterosexual individuals (odds ratios = 1.47-3.82). Furthermore, when dysfunction/impairment associated with criterion endorsement was ignored, endorsement disparities were magnified. Diagnostic/criterion differences were mostly explained by transdiagnostic factor differences associated with sexual minority status, with some notable exceptions. These results suggest that the predilection toward BPD diagnosis among sexual minority individuals does not appear reflective of criterion-related bias. They further highlight the importance of understanding group-specific forms of psychiatric malaise and reinforce the importance of cultural humility for equitable assessment. These results further raise questions pertaining to the conceptualization and epistemology of BPD as it relates to sexual minority individuals.

The distinction between symptoms and traits in the Hierarchical Taxonomy of Psychopathology (HiTOP)

The Hierarchical Taxonomy of Psychopathology (HiTOP) is an empirically and quantitatively derived dimensional classification system designed to describe the features of psychopathology and, ultimately, to replace categorical nosologies. Among the constructs that HiTOP organizes are "symptom components" and "maladaptive traits," but past HiTOP publications have not fully explicated the distinction between symptoms and traits. We propose working definitions of symptoms and traits and explore challenges, exceptions, and remaining questions. Specifically, we propose that the only systematic difference between symptoms and traits in HiTOP is one of time frame. Maladaptive traits are dispositional constructs that describe persistent tendencies to manifest features of psychopathology, whereas symptoms are features of psychopathology as they are manifest during any specific time period (from moments to days to months). This has the consequence that almost every HiTOP dimension, at any level of the hierarchy, can be assessed as either a trait or a symptom dimension, by adjusting the framing of the assessment. We discuss the implications of these definitions for causal models of the relations between symptoms and traits and for distinctions between psychopathology, normal personality variation, and dysfunction.

A Hierarchical Taxonomy of Psychopathology Can Transform Mental Health Research

For more than a century, research on psychopathology has focused on categorical diagnoses. Although this work has produced major discoveries, growing evidence points to the superiority of a dimensional approach to the science of mental illness. Here we outline one such dimensional system-the Hierarchical Taxonomy of Psychopathology (HiTOP)-that is based on empirical patterns of co-occurrence among psychological symptoms. We highlight key ways in which this framework can advance mental-health research, and we provide some heuristics for using HiTOP to test theories of psychopathology. We then review emerging evidence that supports the value of a hierarchical, dimensional model of mental illness across diverse research areas in psychological science. These new data suggest that the HiTOP system has the potential to accelerate and improve research on mental-health problems as well as efforts to more effectively assess, prevent, and treat mental illness.

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.