Where is Mania in the Hierarchical Taxonomy of Psychopathology: Internalizing, Thought Disorder, or Novel Spectrum?

Objectives: The nosology of mania has long been a conundrum. Prior studies have alternatively concluded it is an internalizing disorder, a thought disorder, or a unique psychopathology. It is possible that mania is distinguished from internalizing and thought disorder by course, or that the structure of mania varies as a function of whether data is collected by self-report or interview. We test the influence of these factors on mania’s placement in the context of internalizing and thought disorder spectra. Methods: We tested four models of mania in sample of 337 individuals assessed 20 years after their first admission for psychosis. Models included data on course of episodes over the 20 years of illness, as well as self-report and interviewer-rated measures of current symptoms. Results: Self-reported mania, interviewer-rated mania, and course of mania formed independent factors. Structural models indicated self-reported symptoms fall on internalizing, interviewer-rated symptoms fall on thought disorder, and the course of mania formed a separate factor. Most of the classic correlates of mania—including family history, genetic risk, early age of symptom onset and neuropsychological function—were associated only with course. Limitations: Limitations include the ascertainment of participants from inpatient facilities, which may not capture less severe mania, and attrition over the 20-year course of the study. Conclusions: Including markers of illness course in structural models of psychopathology reveals that mania is distinguished from internalizing and thought disorder factors by its longitudinal course. These data support a separate mania spectrum, defined by the lifetime pattern of episodes.