<qa>  What is the effect of lamotrigine on bipolar depression?Lamotrigine is an anticonvulsant that prolongs the refractory phase of voltage sensitive channels, an action that is associated with antimanic properties Hurly, 2002; Sporn and Sacks, 1997; Calabrese et al; 1999, Normann et al; 2002. Lamotrigine was postulated to decrease glutamate release by acting at voltage-sensitive sodium channel in their refractory phase, stabilizing presynaptic neuronal membranes and inhibiting pathologic release of glutamate. As abnormalities in glutamatergic system have been implicated in depression, and NMDA receptor antagonists reverse anxiety or depression in various stress models, lamotrigine could act as an antidepressant. . Thus, lamotrigine has a potential to have both antimanic and antidepressant activity for refs, see Sporn and Sacks, 1997, and in theory should be uniquely effective for mixed mania Dilsaver et al, 1999. Indeed, clinical trials reviewed in detail by Hurley 2002, demonstrated that lamotrigine is somewhat effective an antimanic agent, and has significant antidepressant activity in bipolar depression. Lamotrigine was used in a combination with other agents or as monotherapy, and the response rates for depressed, mixed and rapid cycling states were similar, ranging from 52 to 63. With slow dose titration 6 weeks, side effects were few and the incidence of exfoliative dermatitis was 1 in 500. Of note, although Sporn and Sachs 1997 reported a switch from depression to rapid cycling, such incidences were few. In our institution, lamotrigine was effective for treatment of mixed mania and bipolar depression in patients receiving standard maintenance treatment for Bipolar Mood Disorder. Lamotrigine did worsen agitation in two elderly patients with symptoms of irritable mania. 