BackgroundGold-standard psychological and pharmacological treatments for bulimic-spectrum eating disorders only result in remission for around 50% of patients; patients with affective lability and impulsivity represent a subgroup with particularly poor outcomes. Both dialectical behavior therapy (DBT), a treatment for emotion dysregulation, and lamotrigine, a mood stabilizer, have demonstrated promise for targeting affective lability and impulsivity; however, data exploring the combination of these interventions remain limited.ObjectiveWe followed a group of women with recurrent dysregulated eating behaviors (N = 62) throughout intensive DBT treatment and compared the symptom trajectory of those prescribed lamotrigine (n = 28) and those who were not (n = 34).MethodParticipants completed surveys every 2 weeks throughout treatment.ResultsGroup analyses suggested that all participants self-reported decreases in emotional reactivity, negative urgency, and symptoms of borderline personality disorder (BPD). The lamotrigine group reported greater elevations in BPD symptoms at baseline, but demonstrated steeper decreases in emotion and behavioral dysregulation than the non-matched comparison group. Within-subject analyses suggested that within the lamotrigine group, subjects reported greater decreases in symptoms following prescription of lamotrigine.ConclusionsFindings provide initial data suggesting that lamotrigine could be useful as an adjunctive treatment for patients with affective lability and impulsivity.Level of evidenceIV, time series without randomization.