The findings of a double-blind, randomized, controlled trial published in the American Journal of Psychiatry suggest that the anticonvulsant lamotrigine is not cost-effective or clinically effective as a therapy for borderline personality disorder.

Up to 90% of patients with borderline personality disorder are treated with psychiatric medication. Mood stabilizers like lamotrigine are intended to mitigate aggression toward oneself and others. Lamotrigine is already approved for the treatment of bipolar disorder and has been noted for its relative safety.

The authors identified 276 adults with borderline personality disorder, excluding patients with a concurrent psychotic or bipolar disorder, those already taking a mood stabilizer, or those who might become pregnant. Participants were randomly assigned to the placebo or lamotrigine (200 or 400 mg/d) group, with the larger dose reserved for those taking contraceptives.

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At the 52-week follow-up, participants were rated on the Zanarini Rating Scale for Borderline Personality Disorder. Between-group scores showed no significant difference, with a score of 11.3 for those taking lamotrigine and 11.5 for those taking placebo.

Items rating general quality of life also remained similar at the trial’s beginning and end, including depressive symptoms, self-harming behaviors, and social functioning. The cost of care was also comparable between groups.

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The authors commented on the low adherence rate, which was 36% for patients in the lamotrigine group and 42% for those in the placebo group. Data from 195 patients were available at the study’s end. The authors also noted that participants had relatively high rates of contact with researchers, as many had the drug or placebo delivered in person.

The authors discouraged physicians from the prescription of lamotrigine, despite the “considerable pressure” that may be created by its recommendation in certain textbooks.  

Disclosures: Professor Reilly has received project funding from the Drug Safety Research Unit as part of an unrestricted grant provided by Merck. The other authors report no financial relationships with commercial interests.


Crawford MJ, Sanatinia R, Barrett B, et al. The clinical effectiveness and cost-effectiveness of lamotrigine in borderline personality disorder: a randomized placebo-controlled trial [published online April 6, 2018]. Am J Psychiatry. doi:10.1176/appi.ajp.2018.17091006