Cycloid Psychosis Comorbid with Prader-Willi Syndrome: A Case Series.

Psychosis is a relatively common psychiatric phenomenon seen in patients with Prader-Willi Syndrome (PWS). However, the presentation is atypical and difficult to classify within currently defined affective or psychotic disorders. This distinct presentation may be better understood as a phenomenon called "cycloid psychosis," described as an episodic psychosis with rapid full recovery between episodes.