Gender differences in a cohort study of 604 bipolar patients: The role of predominant polarity

BackgroundSome clinical differences between gender regarding the course and outcome of bipolar disorders have already been described and some others remain still controversial.AimsTo explore gender differences regarding clinical and socio-demographic characteristics amongst bipolar patients with particular attention to predominant polarity and depressive symptoms.MethodData were collected from DSM-IV type I and II bipolar patients (n = 604), resulting from the systematic follow-up of the Bipolar Disorders Program, Hospital Clinic of Barcelona, over an average follow-up of 10 years. Socio-demographic and clinical variables were collected in order to detect gender-related differences.ResultsBipolar women are more likely than men to show a predominance of depressive polarity as well as a depressive onset whilst men would be more likely to suffer from comorbid substance use disorders. Women significantly have a higher lifetime prevalence of psychotic depression and a higher prevalence of axis II comorbid disorders. Bipolar women are also more likely to have a family history of suicide and a lifetime history of attempted suicide. Suicide attempts are more often violent amongst bipolar men. In a backward logistic regression model, two variables were responsible for most gender-related clinical differences: type of predominant polarity – more likely to be depressive amongst women – (B = − 0.794, p = 0.027, Exp(B) = 0.452; CI =  0.223–0.915), alcohol abuse (B = − 1.095, p = 0.000, Exp(B) = 2990; CI =  1.817–4.919) and cocaine abuse (B = 0.784, p = 0.033, Exp(B) = 2.189; CI =  1.066–4.496) – more prevalent amongst men.ConclusionThe main characteristic featuring bipolar women is depression, both at illness onset and as a predominant polarity all along the illness course. This may have important diagnostic and therapeutic implications.