En Europe, environ 10 % des homicides sont commis par des personnes souffrant de troubles psychotiques, certains de ces patients pouvant récidiver dans leur conduite criminelle. Trois observations de délirants persécutés meurtriers sont présentées. Les deux premières concernent des schizophrènes qui, par vengeance, tuèrent dans la rue et dans un hôpital psychiatrique des personnes inconnues. Leurs crimes se caractérisaient par un niveau élevé d’organisation. La troisième observation concerne un paranoïaque hospitalisé d’office, auteur d’une récidive d’homicide sur sa mère lors d’une sortie de week-end. Ce matricide était, à l’inverse, de nature totalement émotionnelle et désorganisée. Les facteurs généraux et psychopathologiques liés à la violence physique des psychotiques sont ensuite analysés à travers ces trois observations et une revue de la littérature. Les relations entre le degré d’organisation psychologique et celui du mode opératoire sont discutées. Il paraît maintenant indispensable de mettre en place, dans notre pays, une procédure scientifique d’évaluation de la dangerosité pour les malades mentaux graves et les auteurs de crimes violents.

The statistically positive correlation between severe mental disorders and physical violence has now been firmly established by international studies. In Europe, about 10% of homicides are committed by psychotic patients who may re-offend. Three medicolegal observations of homicides with bodily mutilation are presented. The first concerns a 31-year-old schizophrenic man who killed a passer-by in the street when in a state of paranoid delusion with themes of homosexual rape and persecution. The crime was committed in two separate phases: first, emotional violence and then, a few hours later, operational utilitarian violence with amputation of the victimʼs hands. The second case concerns a 21-year-old man suffering from paranoid schizophrenia associated with an antisocial personality disorder. During the night, he assassinated two women who worked in a psychiatric unit, one of whom was decapitated while still alive. Although living freely in the community, the patient acted with premeditation and method under the influence of ideas of persecution and cosmic supernatural terror. The third case concerns a 30-year-old man who had been forcibly hospitalized in a psychiatric unit for delusional disorder of persecution with paranoiac personality disorder. During a period of weekend leave, he killed his own mother in the family home in a totally disorganized emotional moment of acting out, then cut off her leg and threw it out of the window. Six years beforehand, he had already killed a prison inmate who was sharing his cell. In the first two cases, the patients’ behavior was partially or totally organized despite delusional motives of paranoid type. In the light of these three dramas and a litterature review, the main psychopathological predictors of physical violence committed by psychotic patients are discussed: severe psychotic episode, persecutory delusional beliefs, comorbidity with substance abuse (alcohol, cannabis) and personality disorders, little or no antipsychotic treatment, and poor therapeutic compliance. In France, it appears mandatory to apply a rigorous procedure for evaluating the dangerousness of severe mental patients and violent criminals.