Informing the Dimensional Classification of Mania: A Daily Diary Study of Symptom-Level Structure

The optimal classification of mania within dimensional models such as the Hierarchical Taxonomy of Psychopathology remains unclear, although progress has been made recently. We extend dimensional classification research by assessing mania and other domains at the symptom-level using a longitudinal, daily diary design (7-day period). Participants (N = 230; 1,243 total surveys) were adults recruited online based on having a self-identified history of significant mental health issues. Consistent with recent cross-sectional research, mania symptoms associated strongly with thought disorder at the between-person level, while also associating strongly with some externalizing features. At the within-person level, specific mania symptoms were more distinctive from other symptoms assessed, but still associated robustly with thought disorder overall. Other symptoms such as euphoric mood also had strong negative within-person associations with internalizing symptoms. These findings provide insights into classifying mania dimensionally and towards studying mania and other symptoms more comprehensively in future longitudinal research.