Mortality in 497 patients with affective disorders attending a lithium clinic or after having left it

Abstract

The impact of lithium prophylaxis on mortality has been studied in 497 patients, 405 bipolars and 92 unipolars, who attended the same out-patient lithium clinic for up to 30 years. In order to avoid preselection, no minimum period of lithium treatment was required in our study. Of a total of 6014 patient-years, 4330 were spent in regular contact with the study clinic. General mortality due to natural causes was not significantly increased; among cardiovascular diseases, only pulmonary embolism showed an excess mortality. No patients died of lithium intoxication or chronic renal insufficiency. Patients were divided into three groups: Group A, 277 patients, attended the study clinic until death or the end of the study, Group B, 86 patients, left the clinic but continued to take lithium, and Group C, 134 patients, both left the clinic and stopped taking lithium. Among bipolars, the suicide rate compared to the general population was in excess in all three groups. Among unipolars, suicides occurred only after the patients had left the study clinic and stopped taking lithium. A special analytical method was used for intergroup comparisons of suicide rates. Bipolars in Group A attending the study clinic regularly had a suicide rate of 3.5 per 1000 patient-years. The rate increased to 6.3 or by 80 % if patients had left the clinic and did not take lithium any longer as in Group C. The suicide rate in Group C increased by 45% compared to Group B, patients who left the clinic but continued to take lithium. Our results support the hypothesis that lithium has a significant antisuicidal effect in bipolars as well as in unipolars. The suicide mortality can be further reduced by regular attendance in a specialised mood disorder clinic.