Are “Euthymic” Patients Really Well?

Clinical trials examining mania or depression generally define euthymia as a symptom rating-scale score below an arbitrary value (often, one third of the initial score). This definition implies that the patient has recovered. A federally funded, multicenter, longitudinal, naturalistic follow-up study of 223 bipolar patients with an index episode of mania or depression calls this assumption into question.

Patients were interviewed every 6 months for 5 years and then annually (median follow-up, 17 years). Following the first episode, all subjects met Research Diagnostic Criteria for recovery (≥8 consecutive weeks with no more than minimal symptoms), but 27% had symptoms falling below the diagnostic threshold for depressive or manic episodes (r…