Clinical characteristics, life adversities and personality traits as predictors of onset or recurrence of affective episodes. A seven-year follow-up study in monozygotic twins

INTRODUCTION: This study investigated whether having a familial risk of affective disorders, subclinical psychopathology, functioning, personality traits, stressful life events, and childhood trauma predict the onset or recurrence of affective episodes.

METHOD: The present study is a 7-year follow-up study of a baseline sample of 204 monozygotic twins (MZ) with unipolar or bipolar disorder in remission or partial remission (affected), their unaffected co-twins (high-risk), and healthy twins with no personal or familial history of affective disorder (low-risk).

RESULTS: During the 7.0-year median follow-up time, 59.3 % of the affected twins had a recurrence of an affective episode, 33.3 % of high-risk twins, and 7.5 % of low-risk twins had an onset. Familial risk and being affected were predictors for onset and recurrence. Including the whole sample, subclinical symptoms, functioning, stressful life events, and the personality trait neuroticism were statistically significant predictors of onset and recurrence. Regarding the individual risk groups, increasing age was a significant predictor of increased hazard in the affected risk group and lower hazard in the low-risk group.

CONCLUSION: This follow-up study revealed that the most potent predictors for onset or recurrence were familial risk and having an affective disorder at baseline. Subclinical depressive symptoms, personality traits, stressful life events, and impaired functioning were significant contributors to onset risk and recurrence. These findings highlight the need to integrate relevant risk factors into daily clinical settings and integrate the most well-established factors as potential targets for primary care interventions.