Suicide mortality in patients on lithium maintenance therapy

Mood disorders are frequently recurrent and it has been shown that maintena nce treatment can reduce long-term morbidity in this condition. It has also been shown that mood disorders carry an increased risk of suicide and that a significant proportion of individuals who commit suicide suffer from a m ood disorder. This paper reports the results of a long term follow-up of a cohort of patients attending a specialist mood disorder clinic over a perio d of 18 years. Sixty-seven suffered from unipolar depression and 36 had bip olar or schizo-affective disorders In order to qualify for entry to the coh ort the unipolar patients had to have had at least three episodes of depres sion and those with bipolar disorders had to have bad at least three episod es - with at least one manic episode and one depressive episode. All patien ts were treated with lithium. The initial treatment refusal rate and drop o ur rates were low. The mortality from suicide in this group was compared wi th that reported in five recent studies - all of which involved patients wh o had not been given maintenance therapy. The standardised mortality ratio (SMR) for all causes for the whole group was 0.93. There were two suicides, In one case the patient had continued treatment with lithium until death a nd in the other the patient had discontinued treatment 12 months before dea th. The overall suicide rate was 1.3 per 1000 patient years. Amongst simila r groups of patients who had not been given maintenance therapy suicide rat es of about 5.5 per 1000 patient years have been reported. It is concluded that maintenance treatment of mood disorders reduces the suicide rate in th is vulnerable group of patients. (C) 1998 Elsevier Science B.V. All rights reserved.