A single dose of lamotrigine induces a positive memory bias in healthy volunteers

Abstract

BackgroundLamotrigine has been shown to be effective in the long-term treatment and relapse prevention of depression in bipolar disorder. However, the neuropsychological mechanisms underlying these effects are unclear. We investigated the effects of lamotrigine on a battery of emotional processing tasks, previously shown to be sensitive to antidepressant drug action in healthy volunteers.MethodsHealthy volunteers (n=36) were randomised in a double blind design to receive a single dose of placebo or 300mg lamotrigine. Mood and subjective effects were monitored throughout the study period and emotional processing was assessed using the Oxford Emotional Test Battery (ETB) 3 hours post administration.ResultsParticipants receiving lamotrigine showed increased accuracy for the recall of positive vs. negative self-descriptors, compared to those in the placebo group. There were no other signficant effects on emotional processing in the ETB, and lamotrigine did not affect ratings of mood or subjective experience.ConclusionsLamotrigine induced a positive bias in emotional memory, similar to the effects of other antidepressants as reported in previous studies. Further work is needed to assess whether similar effects are seen in the clinical treatment of patients with bipolar disorder and the extent to which this is associated with its clinical action in relapse prevention.