Most people with Prader-Willi syndrome (PWS) have difficulty coping with change. This varies from person to person and can be a real problem for those families affected. Change can be anything from a substitute teacher at school, to a different route being taken in a car trip or a new cup being used. Change can also occur suddenly and unexpectedly, as in an electrical blackout. A bad reaction to change may result in the person with PWS refusing to comply with requests, routines or plans and can quickly escalate into perseveration (repeated questions or comments), arguments and aggression. “Shutdown” is another typical response to the anxiety associated with change.These responses can be stressful for families as they often occur at the most inconvenient times.