Key information about psychosis in Prader Willi Syndrome ♦ Prevalence:  • High prevalence of psychosis in mUPD, but also present in delPWS ♦ Onset:  • More likely to be acute onset, at least in mUPD  • Has been reported as early as 8 years old  • Usually during late adolescence or early twenties  • The onset can also occur in adult life ♦ Psychopathology:  • Anxiety, hallucinations and delusions are the most commonly reported symptoms  • Confusional state and motor symptoms often present (catatonia or agitation)  • Most common diagnosis is atypical psychosis, often with cycloid or bipolar components ♦ Treatments:  • Treatment with Risperidone seems promising  • Overall a good recovery between episodes