Identifying factors that predict conversion from depression to bipolar disorder may be useful for early recognition and appropriate treatment of bipolar disorder. The current study examined 1) whether anger, measured cross-sectionally, differed in patients who converted to bipolar disorder compared to patients with remitted or current unipolar depression; and 2) whether aggression reactivity prospectively predicted conversion to bipolar disorder. Data were from the Netherlands Study of Depression and Anxiety, which is an ongoing longitudinal cohort study of adults (18-65 years old). Cross-sectional analysis at the 4-year follow-up period (N=1,585; 68.8.% female) indicated that 4.9% of patients converted from depression to bipolar disorder. Patients who converted to bipolar disorder reported more trait anger (F(2, 1582)=8.20, p<0.001) and aggression reactivity (F(2, 1456)=5.61; p=0.004) compared with patients with remitted and current depression. Converted patients also reported more anger attacks (𝛘2(2)=4.55, p=0.041), antisocial personality traits (𝛘2(2)=5.12, p=0.02), and borderline personality traits (𝛘2(2)=10.41, p=0.001) compared with patients with remitted depression, but not those with current depression. Prospective analyses (N=1,744; 68.3% female) indicated that patients with higher levels of aggression reactivity at baseline had higher conversion rates to bipolar disorder at the 4-year follow-up than those with lower levels of aggression reactivity (hazard ratio=1.4, p=0.37). Feelings of anger might be an important target, perhaps in combination with other clinical features (e.g., family history of bipolar disorder), for early recognition of illness and intervention in bipolar disorder. Moreover, aggression reactivity may be a risk factor for the conversion from depression to bipolar disorder.
Reference:
Mesbah R et al. Depress Anxiety 2021; Epub ahead of print. Abstract
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