The objective of this article was to discuss the concepts of dangerousness and penal responsibility, through the presentation and analysis of the case of a patient with a diagnosis of mental retardation who committed murder. She was found not guilty by reason of insanity and was criminally committed to a forensic hospital in the city of Rio de Janeiro, Brazil. This case shows the importance of psychopathology and forensic psychiatry, which may help the judge to rule about the penal responsibility of an individual with a psychiatric disorder or mental retardation. The investigation of violent behavior of individuals with psychiatric disorders may contribute to increase the understanding and foster the prevention and early treatment of this kind of behaviour.
Violence; commitment of mentally ill; forensic psychiatry; behaviour