• Changes in score of Affective Lability Scale [ Time Frame: Baseline and then weekly for 12 weeks ] [ Designated as safety issue: No ]
• Changes in the score of the Affective Lability Item of the Zanarini Rating Scale for Borderline Personality Disorder [ Time Frame: Baseline and then weekly for 12 weeks ] [ Designated as safety issue: No ]

This study investigates the hypothesis that instability in mood in patients with borderline personality disorder will respond the mood stabilizing medication lamotrigine.

Affective instability is one of the most prominent symptoms in borderline personality disorder. Currently there are no prospective studies of treatment of this symptom with mood stabilizing medications. This study examines the effectiveness of lamotrigine compared to placebo in reducing emotional instability of several types in borderline patients. The types of emotional instability studied involve anger, anxiety, depression, and elation. Subjects entering this 12 week study will be blind to whether they are receiving active medication or placebo. They will be asked to report levels of instability in their mood on a weekly basis. They will also be asked weekly to rate the intensity of other symptoms of borderline personality disorder symptoms, such as unstable relationships, self-harm, and impulsive behaviors.

• Drug: Lamotrigine
• Drug: Placebo

• Weinstein W, Jamison KL. Retrospective case review of lamotrigine use for affective instability of borderline personality disorder. CNS Spectr. 2007 Mar;12(3):207-10.
• Tritt K, Nickel C, Lahmann C, Leiberich PK, Rother WK, Loew TH, Nickel MK. Lamotrigine treatment of aggression in female borderline-patients: a randomized, double-blind, placebo-controlled study. J Psychopharmacol. 2005 May;19(3):287-91.
• Pinto OC, Akiskal HS. Lamotrigine as a promising approach to borderline personality: an open case series without concurrent DSM-IV major mood disorder. J Affect Disord. 1998 Dec;51(3):333-43.

Inclusion Criteria:

• Clinical Diagnosis of Borderline Personality Disorder with high levels of emotional instability

Exclusion Criteria:

• Clinical diagnosis of Bipolar Disorder
• Clinical diagnosis of psychiatric disorder related to general medical condition
• Clinical diagnosis of substance abuse disorder within the last 60 days
• Clinical diagnosis of psychotic disorder
• Previous treatment with lamotrigine
• Pregnancy or nursing
• Currently hospitalized
• Active suicidal or homicidal ideation