Because of similar symptoms of depression, bipolar disorder and borderline personality disorder may be misdiagnosed or confused with one another.

In a new study, researchers reveal the distinct differences between bipolar and borderline personality disorders in order to better treat both.

An individual with bipolar disorder has cyclical changes in mood, energy and activity levels that range from deep depression, to mania or hypomania. A person with borderline personality disorder has trouble regulating emotions and thoughts, and has impulsive and reckless behavior and unstable relationships with others.

The findings reveal that patients with borderline personality disorder are more likely to have additional disorders and also more likely to have experienced childhood trauma than those with bipolar disorder. They may also experience longer and more severe episodes of depression.

The study involved interviewing 268 participants between 1995 and 2012. Of these, 62 participants were diagnosed with bipolar II depression and 206 participants were diagnosed with major depressive disorder with co-occurring borderline personality disorder (MDD-BPD).

Depressive episodes are a considered a part of bipolar disorder, but depression is a separate disorder that can co-occur with borderline personality disorder.

All the participants were between the ages of 18 and 68, and could only have one of the two disorders — not both. They also had to meet the official criteria for experiencing a major depressive episode at the time of the interviews.

The findings showed that the average age of the patients in the MDD-BPD group was 33 years old, versus 37 years old in the bipolar group. The MDD-BPD patients were also less likely to be married. For both groups, the average age of onset was below 20 years old.

Between the two groups, there were no major differences in race, education level, gender, the average number of psychiatric hospitalizations or amount of time spent away from work during the previous five years.

Furthermore, 38 percent of the MDD-BPD group was diagnosed with three or more non-personality disorders (anxiety, mood and eating disorders) compared to 26 percent of the bipolar group.

Thirty percent of the MDD-BPD group was diagnosed with post-traumatic stress disorder compared to 10 percent of the bipolar group.

Patients in the MDD-BPD group also had longer depressive episodes, were more depressed overall, had a harder time doing day-to-day activities, and had significantly more childhood trauma events — especially physical neglect — than the bipolar group. This group was also more suicidal, with twice as many MDD-BPD participants as bipolar participants reporting three or more suicide attempts.

The only factor found to be more common in the bipolar group was having an immediate family member with a history of bipolar disorder.

The lead author of this study was Mark Zimmerman, M.D., from the Department of Psychiatry at Rhode Island Hospital and the Department of Psychiatry and Human Behavior at Brown Medical School.

Source: Journal of Clinical Psychiatry

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Study Probes Distinctions Between Bipolar, Borderline Personality Disorder