Successful risperidone treatment for behavioral disturbances in Prader–Willi syndrome

Prader–Willi syndrome (PWS) is characterized by perinatal muscular hypotonia, dysmorphic features and infancy feeding problems, followed by overeating and being excessively overweight and other symptoms related to hypofunctioning of the hypothalamus (i.e. hypogonadism, short stature and hypopigmentation) including learning disorders. PWS represents the most common diagnosable genetic obesity syndrome. It occurs in approximately one in 15 000 births, and it is associated with chromosomal paternal deletion or maternal disomy at 15q11–q13. In addition to physical features such as obesity, PWS also includes behavioral disturbances such as stubbornness, impulsiveness, aggressiveness, self-mutilation, skin picking, and temper tantrums. Behavioral disturbances (i.e. hyperphagia, morbid obsession, reduced satiety, stealing money to buy food), decreased energy expenditure and reduced physical activity may lead to morbid obesity accompanied by life-threatening cardiacrespiratory complications. Therefore, various modes of psychotropic medications have been suggested, among them selective serotonin reuptake inhibitors, central nervous system stimulators, lithium, anticonvulsant medications (valpro acid, carbamazepine, etc.) and classical neuroleptics. However, to date, no proven and efficient management modality for the behavioral manifestations in PWS has yet been established. Risperidone, an atypical antipsychotic agent, is a highly potent antagonist against both dopamine D2 and serotonin 2A receptors. Our decision to choose risperidone for the treatment of PWS was motivated by a recent report that described risperidone as being effective for children suffering from autism with behavioral disturbances including stubbornness and impulsiveness, which are similar to those of PWS. We herein report a case of PWS, in which risperidone improved the behavioral disturbances and also resulted in weight loss due to the introduction of cognitive behavioral therapy without any side-effects. Case report