[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). The interventions followed the mediating concept, including both female teachers and the mother of the boy. They were instructed to set effective demands, to give positive reinforcement for following rules and to sanction deviant behaviour by over correction. The effects of the intervention were measured through four problem behaviours (oppositional defiant behaviour, self-injurious behaviour, aggressive behaviour against others, evading) with 80 measurements in a multiple baseline analysis (replication over behaviours). The interventions reduced the destructive behaviours of the boy. A follow-up after 10 months proved that no problem behaviours were noticeable anymore.