Self-injurious behavior and serotonin in Prader-Willi syndrome.

Low central nervous system (CNS) serotonin levels have been associated with impulsive, aggressive and self-injurious behavior (SIB). Persons with Prader-Willi Syndrome (PWS) often engage in self-injury by severe compulsive skin picking and gouging and often manifest compulsive eating, hoarding, and explosive outbursts. Some of the compulsive behaviors seen in patients with obsessive-compulsive disorder (OCD) bear similarity to behaviors associated with PWS: Skin picking, trichotillomania, and onychophagia (nail biting). There is abundant evidence that selective serotonin reuptake inhibitors (SSRIs) are effective in treating OCD. Three cases are described in which persons with PWS responded favorably to SSRI treatment. Two persons showed a significant decrease in skin picking. The third case showed a significant decrease in hoarding and explosive outbursts. Strategies are discussed for investigating the possibility of a shared neurochemical basis for the self-injurious, aggressive, and compulsive behaviors in persons with PWS. PWS may provide a relatively homogenous model for the study of skin picking and explosive outbursts among other populations.