The p Factor

TLDR

Mental disorders have traditionally been seen as distinct, episodic categories, but evidence shows they are often sequentially comorbid, recurrent, and exist on a continuum. The study used the Dunedin Multidisciplinary Health and Development Study to examine psychopathology structure over 20 years, accounting for dimensionality, persistence, co‑occurrence, and sequential comorbidity. The analysis revealed that a single general psychopathology dimension—termed the p factor—better explains psychiatric disorders than three separate factors, and higher p scores predict greater life impairment, familiality, adverse developmental histories, and early brain dysfunction, underscoring the challenge of disorder‑specific interventions and supporting transdiagnostic research.

Abstract

Mental disorders traditionally have been viewed as distinct, episodic, and categorical conditions. This view has been challenged by evidence that many disorders are sequentially comorbid, recurrent/chronic, and exist on a continuum. Using the Dunedin Multidisciplinary Health and Development Study, we examined the structure of psychopathology, taking into account dimensionality, persistence, co-occurrence, and sequential comorbidity of mental disorders across 20 years, from adolescence to midlife. Psychiatric disorders were initially explained by three higher-order factors (Internalizing, Externalizing, and Thought Disorder) but explained even better with one General Psychopathology dimension. We have called this dimension the p factor because it conceptually parallels a familiar dimension in psychological science: the g factor of general intelligence. Higher p scores are associated with more life impairment, greater familiality, worse developmental histories, and more compromised early-life brain function. The p factor explains why it is challenging to find causes, consequences, biomarkers, and treatments with specificity to individual mental disorders. Transdiagnostic approaches may improve research.