A preliminary study of lamotrigine in the treatment of affective instability in borderline personality disorder

Abstract

The objective of this study was to evaluate the effectiveness of lamotrigine in reducing affective instability in borderline personality disorder (BPD). We conducted a 12-week, double-blind, placebo-controlled study of 28 patients who met Revised Diagnostic Interview for Borderlines and Diagnostic and Statistical Manual of Mental Disorders, fourth edition criteria for BPD. Patients could not meet Diagnostic and Statistical Manual of Mental Disorders, fourth edition criteria for bipolar disorder. Patients could be taking one antidepressant during the study. Patients were randomly assigned to treatment with flexible-dose lamotrigine or placebo in a 1 : 1 manner. The primary outcome measures were: (i) the Affective Lability Scale total score; and (ii) the Affective Instability Item of the Zanarini Rating Scale for Borderline Personality Disorder (ZAN-BPD). The study randomized 15 patients to receive lamotrigine and 13 patients to receive placebo. Patients in the lamotrigine group had significantly greater reductions in the total Affective Lability Scale scores (P<0.05) and significantly greater reductions in scores on the affective instability item of the ZAN-BPD (P<0.05). A secondary finding was that patients in the lamotrigine group had significantly greater reductions in scores on the ZAN-BPD impulsivity item (P = 0.001). Results from the study suggest that lamotrigine is an effective treatment for affective instability and for the general impulsivity characteristic of BPD.