Suicide is a much feared consequence of depression and carries a huge human cost for the individuals, their families and associates. Persons who suffer from a severe depression with melancholic or psychotic features show a particularly high risk of committing suicide. This book first gives some brief examples of the culture and history and the major aspects of suicide research. A long-term investigation into 89 suicide victims and matched controls is presented, by gender. Risk factors for suicide were found, i.e. brittle/sensitive personality in men. In men “suicidal ideation beyond one''s own will” was related to suicide. The first suicide attempt was more often severe among female suicide victims, as opposed to the controls who made severe attempts later in their career. Late mortality was investigated. Finally, continuation treatment with antidepressant pharmacotherapy after ECT seemed to be preventive of suicide in severe depression. The investigation may help shed light on risk judgement, the suicidal process and possibilities of prevention of suicide. It may be valuable for professionals dealing with suicidal people and also researchers in the field of suicidology.