Objective: To explore the clinical characteristics of familial and non-familial bipolar disorder.
Method: Twenty subjects with bipolar disorder, who also had a family history of bipolar disorder in a first degree relative, were matched for current age, age of first onset of bipolar disorder and gender with 20 subjects with bipolar disorder who had no family history of any psychiatric disorders in first or second degree relatives.
Results: Fourteen subjects in each group were female. The mean age at interview was 45.2 years and the mean age at first admission was 26 years. Although familial and non-familial probands had an equivalent number of illness episodes, familial probands were significantly more likely to experience mixed states as compared to non-familial probands. The latter experienced significantly more depressive episodes and had significantly higher neuroticism (N) scores on the Eysenck Personality Inventory (EPI; Eysenck H, Eysenck S. Manual of the Eysenck Personality Inventory. London: University of London Press, 1964.).
Conclusions: If the results are replicated, they have important implications. For example, such data may aid decisions about the targeting of additional psychosocial interventions in high N score cases. Researchers will wish to investigate whether mixed states show a stronger association with early age of onset or family history of BD.