How is bipolar disorder diagnosed and classified?

Diagnosis of bipolar disorder is challenging because some of its characteristic symptoms (i.e., those associated with mania, depression, and psychosis) are also seen in other psychiatric disorders. Moreover, there is no specific symptom or biochemical feature unique to bipolar disorder. Therefore, bipolar disorder (like most psychiatric disorders) must be diagnosed based on the array of symptoms and course of the condition, plus other relevant factors, such as family history.

As in diagnosing schizophrenia, it is important to rule out medical conditions or other factors that may mimic the symptoms of bipolar disorder. This is necessary to ensure that appropriate treatment is selected. The differential diagnosis of bipolar disorder can be divided into three broad categories:

  • medical factors
  • pharmacologic factors (e.g., certain analgesics, antibacterial and antifungal agents, antihypertensives, antineoplastics, steroids, and neurologic and psychiatric drugs)
  • other psychiatric disorders