Objectives: The prevalence of bipolar affective disorder appears to be equal for men and women, taking a lifetime perspective. However the types of symptoms, course and outcome for the disorder can vary with the sex of the patient. Our study " The Bipolar Comprehensive Outcomes Study (BCOS) " provides a rich data base to examine gender differences in the symptoms, course and outcomes for people with bipolar disorder

Methods: BCOS is a naturalistic observational study of patients, observed over 2 years. Results using a gender based analysis will be presented

Results: Gender differences in psychopathology, social functioning and treatment response will be presented

Conclusion: Gender is a key variable that needs careful consideration when tailoring treatment for bipolar disorder.