Negative symptoms in the Hierarchical Taxonomy of Psychopathology: Nosology, etiology, and pathophysiology

This review examines negative symptoms in the context of the Hierarchical Taxonomy of Psychopathology (HiTOP) model of psychopathology. The HiTOP model was developed as an alternative to traditional psychiatric diagnoses-improving reliability, parsing heterogeneity, and accounting for patterns of comorbidity--thus advancing the ability of researchers and clinicians to understand negative symptoms. In the current HiTOP model, negative symptoms are components of the psychoticism (thought disorder) spectrum alongside positive symptoms and disorganization, though recent HiTOP consortium publications suggest it may be more closely associated with the detachment spectrum. The primary objective of this review is to determine which placement is correct and the implications of this placement for HiTOP and negative symptoms research. In particular, factor analytic research that has emerged since the initial publication of the HiTOP model suggests that negative symptoms can be fully accounted for by the detachment spectrum, alongside personality traits and disorders related to detachment (avoidant, schizoid, extraversion, etc.). In addition, the etiological, developmental, neurobehavioral, and treatment research literatures are reviewed from the perspective of how existing evidence may fit this revised conceptualization of negative symptoms and psychosis. Overall, these research areas provide support for distinctions between psychoticism and detachment in the HiTOP model. Finally, recommendations are offered regarding how the HiTOP model may be further advanced and how researchers and clinicians may benefit from this approach to understanding negative symptoms.