This study examined how the dynamics of four dimensions of affect—sadness, anxiety, activation, and energy—differ between individuals with bipolar disorder (BD) and major depressive disorder (MDD). Participants, aged 11-85 years, reported their momentary states four times a day over two weeks. The study compared those with bipolar-I, bipolar-II, and MDD, as well as controls without psychiatric disorders, using ecological momentary assessment (EMA). Multivariate dynamic structural equation models were used to analyze the data, including random effects, inertias, variances, and cross-lags among the four dimensions of affect.

The results indicated that all mood disorder subtypes were associated with higher sadness and anxiety, and lower energy compared to controls. Patients with Bipolar-I showed lower activation and energy, independent of activation, compared to patients with MDD and controls, with activation increases more likely to perpetuate in bipolar-I. Bipolar-II patients experienced higher variability in sad and anxious mood compared to bipolar-I and controls, but not MDD. Patients with MDD exhibited cross-augmentation of sadness and anxiety, with sadness blunting energy. These findings suggest that bipolar-I is more strongly characterized by activation and energy, which may inform more specific intervention targets and highlight different pathways in the affective systems of BD and MDD.

Reference: Stapp EK, Zipunnikov V, Leroux A, Cui et al. Specificity of affective dynamics of bipolar and major depressive disorder. Brain Behav. 2023 Sep;13(9):e3134. doi: 10.1002/brb3.3134. Epub 2023 Aug 13. PMID: 37574463; PMCID: PMC10498074.