summary
Interest in the neurobiology of criminal behaviour is increasing. Recent research emphasises the important role played by the frontal lobe in the processing of emotional and social information and in the controlling of behaviour. Damage to specific frontal structures in the brain may therefore lead to antisocial and criminal behaviour. On the basis of the case histories of two suspects with brain lesions, the impact of such damage on the forensic psychiatric diagnosis is discussed. A plea is made for the more frequent involvement of a neurologist in the diagnostic evaluation usually undertaken by the forensic psychiatrist.