Bipolar disorder is under-recognized and inadequately treated in primary care, resulting in worsening of symptoms, decreased levels of functioning, and increased risk of suicide. This project is using a practice-based research network to estimate the prevalence of bipolar disorder in family practice. Simultaneously, a diagnostic instrument called the M.I.N.I is tested for its usefulness in primary care. The overall goal of this project is to identify appropriate screening methods in order to make early and correct diagnosis of the bipolar spectrum of disorders in primary care.