A hierarchical causal taxonomy of psychopathology across the life span.

Abstract

We propose a taxonomy of psychopathology based on patterns of shared causal influences identified in a review of multivariate behavior genetic studies that distinguish genetic and environmental influences that are either common to multiple dimensions of psychopathology or unique to each dimension. At the phenotypic level, first-order dimensions are defined by correlations among symptoms; correlations among first-order dimensions similarly define higher-order domains (e.g., internalizing or externalizing psychopathology). We hypothesize that the robust phenotypic correlations among first-order dimensions reflect a hierarchy of increasingly specific etiologic influences. Some nonspecific etiologic factors increase risk for all first-order dimensions of psychopathology to varying degrees through a general factor of psychopathology. Other nonspecific etiologic factors increase risk only for all first-order dimensions within a more specific higher-order domain. Furthermore, each first-order dimension has its own unique causal influences. Genetic and environmental influences common to family members tend to be nonspecific, whereas environmental influences unique to each individual are more dimension-specific. We posit that these causal influences on psychopathology are moderated by sex and developmental processes. This causal taxonomy also provides a novel framework for understanding the heterogeneity of each first-order dimension: Different persons exhibiting similar symptoms may be influenced by different combinations of etiologic influences from each of the three levels of the etiologic hierarchy. Furthermore, we relate the proposed causal taxonomy to transdimensional psychobiological processes, which also impact the heterogeneity of each psychopathology dimension. This causal taxonomy implies the need for changes in strategies for studying the etiology, psychobiology, prevention, and treatment of psychopathology.

Delineating the joint hierarchical structure of clinical and personality disorders in an outpatient psychiatric sample

“…Although the focus on only maladaptive behaviors and traits in the present study means that the general factor may be a positive manifold in this instance [i.e., a consequence of the systematic positive correlations among all the indicators, cf. 26], there is a growing body of evidence supporting the validity and utility of a factor representing the general propensity towards psychopathology [e.g., 32]. We discuss the lower tiers of the hierarchy—one branch of the hierarchy at a time—in the context of the extant literature below.…”

“…Similarly, analyses of clinical disorders have found an interpretable hierarchy that includes the three core dimensional spectra, their narrower nested components, and a higher-order general factor. This higher-order factor represents a general propensity towards psychopathology, and is hypothesized to account for shared, nonspecific etiologic mechanisms that span multiple dimensions of psychopathology [30–32]. Hierarchical models of these dimensional factors of clinical disorders have been found to maintain reliability and validity, with each level differentially predicting important outcomes such as psychosocial functioning, and disorder onset and maintenance [33, 34].…”

“…Further, a joint hierarchy—based on robust representation of both clinical and personality disorders—could clarify the nature and boundaries of the shared underlying dimensions of psychopathology. Such a model may also pave the way toward more replicable and accurate etiologic research [21, 32]. …”

A polygenic p factor for major psychiatric disorders

“…However, these higher-order dimensions also correlate with each other 3 , which suggests the possible existence of a general factor of psychopathology 4 . This general factor has been called the p factor 5 as it captures the shared variance across psychiatric symptoms, and predicts a multitude of poor outcomes and general life impairment 6,7 .…”

Don’t blame the model: Reconsidering the network approach to psychopathology.

“…Let us start with assuming that latent variable models should indeed be interpreted as common cause models, as has been argued by authors advocating the network approach (see also Lahey, Krueger, Rathouz, Waldman, & Zald, 2017;van Bork, Wijsen, & Rhemtulla, in press). As we will explain, common cause models are in fact more complex and flexible than has been assumed in the psychological network literature: even if symptoms of a disorder have a common cause, this does not imply that the symptoms do not directly interact with each other (Danks et al, 2010;Haig & Vertue, 2010;Haslam, 2010;Humphry & McGrane, 2010).…”