SEASONAL MOOD CHANGE AND PERSONALITY - AN INVESTIGATION OF GENETIC CO-MORBIDITY

Clinical observations and empirical studies suggest that Seasonal Affe ctive Disorder (SAD) is related to personality. The present study esti mates the genetic and environmental correlations between the Global Se asonality Score (GSS) from the Seasonal Pattern Assessment Questionnai re and personality measures, assessed using the NEO Five Factor Invent ory (NEO-FFI) and the Dimensional Assessment of Personality Pathology (DAPP) in a volunteer sample of 163 monozygotic (MZ) pairs (102 female and 61 male pairs) and 134 dizygotic (DZ) pairs (70 female, 38 male a nd 26 opposite-sex pairs). Large genetic correlations were found betwe en the GSS and NEO-FFI Neuroticism (0.52: 95% CI = 0.36-0.71) and DAPP -BQ Cognitive Dysregulation (0.50: 95% CI = 0.30-0.71), Affective Labi lity (0.49: 95% CI = 0.29-0.77), Anxiousness (0.37: 95% CI = 0.18-0.55 ) and Stimulus Seeking (0.45: 95% CI = 0.25-0.64) scales. The genetic correlations with the remaining scales, such as Extraversion (0.06: 95 % CI = -0.16-0.26), Compulsivity (-0.09: 95% CI= -0.31-0.12) and Submi ssiveness (0.15: 95% CI = -0.05-0.34) were uniformly small. All enviro nmental correlations between the GSS and personality scales were less than or equal to 0.19. These results provide evidence that the observe d correlations between these seasonality and personality dimensions ar e attributable to common genetic factors and that environmental influe nces are domain specific. (C) 1998 Elsevier Science Ireland Ltd.