Misdiagnosis of bipolar affective disorder as personality disorder

Patients with longstanding recurrent behavioural disturbance, unstable interpersonal relationships and periodic affective symptoms are often diagnosed as having a cluster B personality disturbance using DSM-III-R criteria. Two women are described who were diagnosed as having a personality disorder on several admissions to hospital, but in whom closer inquiry revealed evidence of bipolar affective disorder. Since treatment with lithium and adjunctive mood-stabilizing drugs neither patient has required further admissions to hospital within the past five years.