Depressive Symptoms Dominate the Natural History of Bipolar II Disorder

Laurie Barclay, MD

March 14, 2003

March 14, 2003 — A prospective longitudinal study published in the March issue of the Archives of General Psychiatry maps the natural history of bipolar II disorder (BP-II). Although this is a dimensional illness involving a full severity range of depressive and hypomanic symptoms these patients have a predominance of depressive symptoms.

"This is the first prospective longitudinal study, to our knowledge, of the natural history of the weekly symptomatic status of BP-II," write Lewis L. Judd, MD, from the University of California in San Diego, and colleagues. "Detailed analysis of the full range of affective symptom severity and polarity presents a more complete picture of the long-term symptomatic structure of mood disorders."

During prospective follow-up with mean duration of 13.4 years, 86 patients with BP-II had weekly affective symptom status ratings based on interviews conducted at six- or 12-month intervals.

Patients were symptomatic during 53.9% of all follow-up weeks, with depressive symptoms in 50.3% of weeks, hypomanic symptoms in 1.3% of weeks, and cycling or mixed symptoms in 2.3% of weeks. Subsyndromal, minor depressive, and hypomanic symptoms combined occurred three times more often than did major depressive symptoms.

Factors predicting greater chronicity were longer intake episodes, family history of affective disorders, and poor previous social functioning, but not prescribed somatic treatment. Patients with hypomanic states lasting two to six days were not significantly different in any other measures from those with hypomanic states lasting at least seven days.

"Longitudinally, BP-II is a chronic affective disorder expressed within each patient as a fluctuating dimensional symptomatic continuum, which includes the full severity range of depressive and hypomanic symptoms, but dominated primarily by minor and subsyndromal depression," the authors write. "This study of BP-II prospectively documents the existence of long periods of subthreshold or 'cyclothymic' fluctuations of symptoms between relatively short syndromal affective episodes. To paraphrase Kraepelin, the nature of this deceptively 'milder' form of manic-depressive illness is so chronic as to seem to fill the entire life."

Arch Gen Psychiatry. 2003;60:261-269

Reviewed by Gary D. Vogin, MD


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