[Biological-psychiatric aspects of delinquency and aggression]

After a historical introduction, the author summarizes the findings of biologically oriented psychiatric research on delinquency and aggression. In the field of genetics, twin and adoption studies prove that there must be a strong hereditary factor in the genesis of criminality, although so far only two chromosomal abnormalities have been found which seem to show a comparatively increased tendency to criminal behaviour. In addition, minimal cerebral dysfunction caused by early acquired brain damage, and attention deficit disorder combined with hyperactivity (two types of infantile mental disorder that seem hard to tell apart) are thought to be high risk conditions for criminality.