The suicide-related mortality among patients with affective disorders is approximately 30 times higher, and overall mortality 2 to 3 times higher, than suicide-related mortality in the general population. Lithium has demonstrated possibly specific antisuicidal effects apart from its prophylactic efficacy: it significantly reduces the high excess mortality of patients with affective disorders. To date, suicide-prevention effects have not been shown for antidepressant or anticonvulsant long-term treatment. Clozapine appears to reduce the suicide rate in schizophrenia patients. Against this background, guidelines and algorithms for selecting an appropriate prophylactic strategy for affective disorders should consider the presence of suicidality in patient history. Appropriate lithium prophylaxis prevents approximately 250 suicides yearly in Germany, although lithium salts are infrequently prescribed within the National Health Scheme (specifically, to 0.06% of the population). Rational treatment strategies most likely would demand that prescription rates be about 10 times higher.