[Criminal behavior in frontotemporal dementia and Alzheimer's disease].

Criminal behavior in older people represents a rare phenomenon. Among older criminals there are many first offenders and 75% are men. Dementia poses one possible origin of delinquency in advanced age. It is unclear how often dementia is the actual cause of delinquency in older age. In studies with older criminals the prevalence of dementia was heterogeneous due to methodological study issues. In the course of the disease 50% of patients with frontotemporal dementia and 10% of patients with Alzheimer's disease commit crimes. The neurobiological origin of delinquency in dementia is poorly understood. On the basis of current study results first delinquency in older age can be explained by impairment of social cognition, difficulties in making appropriate emotional contributions and disturbed control of behavior. Affection of frontal and anterior temporal brain structures seem to be of high relevance. As dementia impairs criminal responsibility psychiatrists are confronted with a forensic evaluation of legal culpability of older criminals. Regarding different etiologies of dementia, specific peculiarities need to be considered in a forensic psychiatric assessment. Especially frontotemporal dementia predisposes towards a wide spectrum of criminal behavior whereas patients with Alzheimer's disease predominantly commit crimes due to cognitive impairment. The review summarizes the present knowledge about criminal behavior in the context of dementia.