There are many problems with symptom accuracy, relevance, and reliability in making a diagnosis of bipolar disorder using the DSM-IV-TR. These problems all too often lead to misdiagnosis.
In fact, University of California at San Diego's Hagop Akiskal M.D. believes that the way the bipolar disorders in the DSM are conceptualized and presented routinely lead many primary care doctors and mental health professionals to misdiagnose bipolar patients with unipolar depression, when a careful history from patient, family, and/or friends would yield the correct diagnosis.
If misdiagnosed with depression, patients are usually prescribed antidepressants, and the person with bipolar depression can become agitated, angry, hostile, suicidal, and even homicidal (these are all symptoms of hypomania, mania, and mixed states).
The DSM V will likely address these diagnostic issues when published in 2011