Diagnosing and treating comorbid (complicated) bipolar disorder.

Comorbidity is the rule, not the exception, in bipolar disorder. The most common mental disorders that co-occur with bipolar disorder in community studies include anxiety, substance use, and conduct disorders. Disorders of eating, sexual behavior, attention-deficit/hyperactivity, and impulse control, as well as autism spectrum disorders and Tourette's disorder, co-occur with bipolar disorder in clinical samples. The most common general medical comorbidities are migraine, thyroid illness, obesity, type II diabetes, and cardiovascular disease. Bipolarity is a marker for comorbidity, and comorbid disorders, especially multiple conditions occurring when a patient is young, may be a marker for bipolarity. Relatively few controlled clinical studies have examined the treatment of bipolar disorder in the context of comorbid conditions (i.e., complicated or comorbid bipolar disorder). However, the first step in treating any type of complicated bipolar disorder--stabilizing a patient's mood--may be associated with improving the comorbid disorder. Standard mood stabilizers, atypical antipsychotics, and non-antimanic antiepileptic agents are emerging as potentially useful treatments for several of the disorders that frequently co-occur with bipolar disorder, and therefore may be useful treatments for comorbid bipolar disorder.