Effect of sodium valproate on nocturnal melatonin sensitivity to light in healthy volunteers

Abstract

Sensitivity of the pineal hormone melatonin to bright light at night has been proposed as a putative1 marker of bipolar affective disorder, Patients with bipolar disorder have a super-sensitive melatonin response to light. No studies have investigated whether super-sensitivity is due to agents used to treat the illness or is associated with the disorder per se. We investigated the effect of valproate on this phenomenon. Meiatonin sensitivity to Sight was determined on two nights in 12 healthy volunteers (5M, 7F). Between testing, nights participants received 200 mg of valproate b.d. for 5 days. Valproate significantly decreased the sensitivity of melatonin to light. On the other hand, valpro..