Some conditions misdiagnosed as bipolar disorder

By Amy Norton

NEW YORK (Reuters Health) - A study published last year suggested that bipolar disorder may be over diagnosed in people seeking mental health care. Now new findings shed light on which disorders many of these patients actually have.

Bipolar disorder, also known as manic depression, involves dramatic swings in mood -- ranging from debilitating depression to euphoric recklessness.

In the original 2008 study, researchers at Brown University School of Medicine found that of 145 adults who said they had been diagnosed with bipolar disorder, 82 (57 percent) turned out not to have the condition when given a comprehensive diagnostic interview.

In this latest study, published in the Journal of Clinical Psychiatry, the researchers used similar standardized interviews to find out which disorders those 82 patients might have.

Overall, they found, nearly half had major depression, while borderline personality disorder, post-traumatic stress disorder (PTSD), generalized anxiety and social phobia were each diagnosed in roughly one-quarter to one-third.

When the researchers then compared the patients with 528 other psychiatric patients who had never been diagnosed with bipolar disorder, they found that those in the former group were nearly four times more likely to have borderline personality disorder.

They were also 70 percent more likely to have major depression and twice as likely to have PTSD.

Some of other diagnoses were less common but still seen at elevated rates among the patients previously diagnosed with bipolar disorder. These included antisocial personality disorder and impulse-control disorder.