A Detailed Hierarchical Model of Psychopathology: From Individual Symptoms up to the General Factor of Psychopathology

Abstract

Much of the knowledge about the relationships among domains of psychopathology is built on the diagnostic categories described in the Diagnostic and Statistical Manual of Mental Disorders ( DSM), and relatively little research has examined the symptom-level structure of psychopathology. The aim of this study was to delineate a detailed hierarchical model of psychopathology—from individual symptoms up to a general factor of psychopathology—allowing both higher- and lower-order dimensions to depart from the structure of the DSM. We explored the hierarchical structure of hundreds of symptoms spanning 18 DSM disorders in two large samples—one from the general population in Australia ( n = 3,175) and the other a treatment-seeking clinical sample from the United States ( n = 1,775). There was marked convergence between the two samples, offering new perspectives on higher-order dimensions of psychopathology. We also found several noteworthy departures from the structure of the DSM in the symptom-level data.

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

“…However, the CAT-PD Grandiosity scale administered here primarily assesses entitlement (e.g., "should get special privileges"), which seems less connected to thought disorder. Regarding other discrepancies from the broader HiTOP framework, disinhibited and antagonistic externalizing both traditionally are classified within the broader externalizing domain (Kotov et al, 2017); however, our results and those of other recent studies (Forbes et al, 2021) focusing on homogeneous dimensional ratings indicate that disinhibition overlaps strongly with the internalizing spectrum. Given our reliance on a limited measure set and convenience samples, we are not advocating for drastic reorganization of the HiTOP model based on these results.…”

“…Acknowledging these perspectives, several recent studies indicate that some NDD-relevant features such as communication difficulties may be distinct from well-established HiTOP spectra (e.g., internalizing, detachment; Michelini et al, 2019;Stanton et al, 2021). However, other features described as characteristic of ASD (e.g., social withdrawal) overlap closely with existing HiTOP spectra such as detachment (Michelini et al, 2019;Zimmerman et al, 2021). Furthermore, some structural models classify ADHD dimensions, which have been studied somewhat more widely than ASD in dimensional classification research, within externalizing rather than within a separate NDD spectrum (Andrews et al, 2009).…”

“…Based on the evidence to date, hypomania is classified provisionally within the thought disorder spectrum (Kotov et al, 2020). However, a focus on general composite ratings of hypomania in prior research greatly limits understanding of classification (Forbes et al, 2021). The DSM-5 hypomania criteria are particularly heterogeneous, as they include description of dimensions that may align most closely with several different HiTOP spectra (e.g., irritability with internalizing; distractibility and risk taking with disinhibited externalizing; grandiose delusions with thought disorder; APA, 2013).…”

“…We refer to the sample of community adults as the "online community sample" going forward, and data from this sample were collected at two timepoints approximately 2 weeks apart. Given issues with examinations of psychopathology structures using composite disorder ratings (Forbes et al, 2021), we focused on assessing distinct trait dimensions using an array of self-report scales to assess NDDs, hypomania, and other psychopathology. With use of this self-report assessment approach, we refer to measures used here as indicators of traits relevant to hypomania and NDDs (e.g., "NDD-relevant") rather than indicators of current symptoms exceeding traditionally-defined DSM disorder cutoffs.…”

“…An Initial Investigation of the Joint Classification of Hypomania-and Neurodevelopmental Disorder-Relevant Dimensions within the Hierarchical Taxonomy of Psychopathology The Hierarchical Taxonomy of Psychopathology (HiTOP; Kotov et al, 2017) is an empirically-driven, dimensional classification system with the potential to address limitations of the Diagnostic and Statistical Manual of Mental Disorders (currently fifth edition; DSM-5; American Psychiatric Association [APA], 2013). Although a substantial literature has guided the classification of many symptom dimensions within broad domains such as internalizing and externalizing from a HiTOP perspective, classification of other symptom dimensions, including those associated with DSM neurodevelopmental disorders (NDD) such as attentiondeficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD), remains unclear (Kotov et al, 2017;Zimmerman et al, 2021). The classification of other dimensions related to widely studied disorders such as bipolar spectrum disorders/hypomania also remains uncertain, representing another critical gap that limits the HiTOP's applicability for informing measure development efforts and clinical assessment (Kotov et al, 2020;Watson et al, 2021).…”