[Modification of self-injury and self-mutilation behavior--analysis of a single case intervention study of a boy in a school for mentally retarded].

The present study analysed the self-injurious, destructive behaviour of a mentally retarded boy, ten years of age which was generally noticed through his resistance to demands and because of his self-destructive behaviour and aggressions against others. This behaviour appeared in critical situations (following instructions; not getting something). It is maintained by positive (getting attention) and negative reinforcement (let off demands).