Cancer risk in patients with bipolar disorder and their unaffected siblings

Increasing evidence suggests that patients with bipolar disorder are more likely to develop malignancies compared with the general population. A nationwide population-based study in Taiwan found that patients with bipolar disorder (OR 1.22; 95% CI 1.06-1.40) and their unaffected siblings (1.17; 1.02-1.34) had greater risk of developing cancer than did controls. Among those younger than 50 years, for both patients with bipolar disorder (1.90; 1.38-2.61) and their unaffected siblings (1.65; 1.19-2.28) were more likely to develop ectodermal cancer, especially breast cancer, compared to the control group.