Objective: To examine whether a high genetic liability to develop affective disorder is associated with specific personality traits.
Method: A cross-sectional, high-risk, case-control study. Through nation-wide registers, healthy monozygotic (MZ) and dizygotic (DZ) twins with (high-risk twins) and without (the control group/low-risk twins) a co-twin history of affective disorder were identified. Personality traits were compared for a total of 211 high-risk and low-risk twins.
Results: In univariate analyses, the high-risk twins had a higher level of neuroticism than the control twins (P = 0.03). In multivariate analyses, a high genetic liability to affective disorder was not significantly associated with neuroticism but correlated to sex, minor psychopathology and recent life events.
Conclusion: A high genetic liability to affective disorder showed an association with neuroticism, but the association interacts with other predictors of affective disorder such as female gender, minor psychopathology and recent adversity.