Alcohol and drug abuse are very common among people with bipolar disorder. Research findings suggest that many factors may contribute to these substance abuse problems, including self-medication of symptoms, mood symptoms either brought on or perpetuated by substance abuse, and risk factors that may influence the occurrence of both bipolar disorder and substance use disorders. Treatment for co-occurring substance abuse, when present, is an important part of the overall treatment plan.

Anxiety disorders, such as post-traumatic stress disorder and obsessive-compulsive disorder, also may be common in people with bipolar disorder. Co-occurring anxiety disorders may respond to the treatments used for bipolar disorder, or they may require separate treatment.