Lithium in Unipolar Depression and the Prevention of Suicide

Unipolar depression is a severe recurrent illness with high lifetime morbidity and premature mortalitydue to suicide. Numerous double-blind, placebo-controlled trials have shown that lithium isvery effective at reducing relapses when given as maintenance therapy. It is also very effective whengiven as maintenance therapy after electroconvulsive therapy. It can be given once a day at night, andcontrolled trials have shown a 12-hour plasma lithium level between 0.5 and 0.7 mmol/L the mosteffective, with very slight side effects. Long-term studies of lithium maintenance therapy show a suiciderate of 1.3 suicides per 1000 patient years. This is much lower than comparative studies in longtermfollow-up of untreated depression, which show about 5.5 suicides per 1000 patient years. Althoughit is neither feasible nor ethical to carry out double-blind studies on suicide reduction, themassive evidence showing a reduction in morbidity on lithium treatment suggests that systematiclong-term lithium treatment of unipolar depression could considerably lower the suicide rate.