Temperament, depression make volatile mix.

Stir major depression into an emotionally unstable, self-absorbed personality and you have a recipe for a serious psychiatric disorder that clinicians often misdiagnose, a new study finds.

The disorder, one of two recognized forms of manic depression, often sends individuals careening from 1 to 2 weeks of severe lethargy, withdrawal, and melancholy to several days of elevated or irritable mood, constant activity, and risky decision making. Psychiatrists call this condition bipolar II.

In contrast, bipolar I includes more severe, often incapacitating periods of mania that include hallucinations or delusions.

For people who display a curious excess of emotional turmoil, physical energy, and self-reflection (signaled by frequent daydreaming), the onset of depression usually triggers a switch to bipolar II within 5 years, assert psychiatrist Hagop S. Akiskal of the University of California School of Medicine in San Diego and his colleagues.

"The emotional storms of these patients might represent attempts for self-cure from depressive inertia, [sadness], and self-absorption," Akiskal's team writes in the February Archives of General Psychiatry.

Whatever mental processes underlie bipolar II, it proves difficult to identify, the researchers say. Clinicians often diagnose this condition as borderline personality disorder, which is marked by unstable romantic relationships, manipulativeness, and impulsive acts, but not depression (SN: 3/5/94, p.152).

However, people suffering from this version of manic depression show the greatest improvement, at least in the short run, when given a certain type of antidepressant medication, Akiskal's team notes. These drugs, which block the action of the chemical messenger monoamine oxidase, differ substantially from the standard class of antidepressants, as well as from newer forms, such as fluoxetine (Prozac).

The scientists studied 559 moderately to severely depressed individuals who first sought treatment nearly 20 years ago at one of five university psychiatric centers. After their depression subsided, participants completed personality scales containing 436 items. Experimenters evaluated the volunteers' condition once or twice a year for the next 11 years.

Personality characteristics of 48 people who during that time converted from major depression to bipolar II were compared with those of 22 who developed full-blown manic depression and with the remainder, who displayed only bouts of depression.

Bipolar II converters cited a personality profile that departed strikingly from those of the other two groups, the investigators contend. It revolved around an unstable temperament that featured sharp ups and downs in emotion, relentless pursuit of activities and work, and intense self-absorption fueling a penchant for daydreaming.

"This study should alert clinicians to monitor closely patients with both depression and personality traits that create mood instability," holds Robert M.A. Hirschfeld, director of psychiatry and behavioral sciences at the University of Texas Medical Branch in Galveston. "We should be cautious about using [standard] antidepressants in these cases."

The new report is part of a larger, federally funded project to study different aspects of depression that Hirschfeld formerly directed.

"Given current financial constraints, there may not be another longitudinal project like this for some time," the Texas psychiatrist contends. "That makes its results even more significant."