The media coverage of a few homicides committed by psychotic obviously raises questions about the dangerous and violent nature of the mentally ill. Firmly rooted in the collective consciousness is the popular idea that someone who kills an unknown person in the street is mentally ill. On the contrary the epidemiological data are reassuring; only 15% of such murders are committed by the seriously mentally ill (schizophrenia, paranoia, melancholia).

Typing and comparison of murders committed by schizophrenic, paranoiac and melancholic persons.

We consulted and analysed 268 expertises from two psychiatrists. This retrospective study shows several types of pathological murder (schizophrenia, paranoiac delirious disorder, affective disorder: melancholia and hypomania).

From these 268 cases of homicide examined, 27 murderers were psychotic.

Ten of these were young, single, jobless, male paranoid schizophrenics: they drank little alcohol. Most of them have criminal history. They knew their victim (family, friends).

Nine others were paranoiac, for the most part male, older, married, family men, without psychiatric or criminal record. They murdered their wife or husband or neighbour. Alcoholic consumption is often involved. Schizophrenic and paranoiac murderers often have an emotional temper.

On the contrary, melancholic murderers are mostly female, aged around 30, married, family women, drinking little alcohol. Two third of them have psychiatric depressive record and had bipolar troubles and attempted suicide. Their murders are more often premeditated. They know the victim: child or partner. Suicide often follows the murder.