Study of Lamotrigine Treatment of Affective Instability in Borderline Personality Disorder

Subject in active active drug group will receive lamotrigine tablets 12.5 per day for the first week of the study. Dose of lamotrigine can be increased to 25mg per day during the second week of the study and may be increased each week thereafter for the next 9 weeks by 25mg per day. Subjects in active treatment group will receive lamotrigine for total of 12 weeks

Subjects will receive 12.5mg of inert placebo per day during the first week of the study. Inert placebo can be increased to 25mg per day during the second week of the study and by 25mg per day each week for the next 9 weeks. Subjects can receive a total of 12 weeks of placebo.