Diagnosing Bipolar Disorder and the Effect of Antidepressants: A Naturalistic Study.

Objectives: To determine if bipolar disorder is accurately diagnosed in clinical practice and to assess the effects of antidepressants on the course of bipolar illness.

Method: Charts of outpatients with affective disorder diagnoses seen in an outpatient clinic during 1 year (N = 85 with bipolar or unipolar disorders) were reviewed. Past diagnostic and treatment information was obtained by patient report and systematic psychiatric history. Bipolar diagnosis was based on DSM-IV criteria using a SCID-based interview.

Results: Bipolar disorder was found to be misdiagnosed as unipolar depression in 37% of patients who first see a mental health professional after their first manic/hypomanic episode. Antidepressants were used earlier and more frequently than mood stabilizers, and 23% of this unselected sample experienced a new or worsening rapid-cycling course attributable to antidepressant use.

Conclusion: These results suggest that bipolar disorder tends be misdiagnosed as unipolar major depressive disorder and that antidepressants seem to be associated with a worsened course of bipolar illness. However, this naturalistic trial was uncontrolled, and more controlled research is required to confirm or refute these findings.

J Clin Psychiatry 2000;61(10):804-808