Tentative classification of neuropsychiatric disturbances in Prader-Willi syndrome.

Doctors looked at a small group of people with Prader-Willi syndrome. They wrote down the kinds of mental-health problems each person showed. The team then sorted the problems into three simple buckets: explosive-oppositional, psychotic, or refusal-lethargy. No treatment was tested; they just described what they saw.

Every person fit one of the three buckets. Some had angry outbursts and defiance. Others heard voices or held false beliefs. The rest were quiet, slow, and withdrawn. The authors said these buckets might help doctors pick medicines later.

Sinnema et al. (2011) later counted real numbers in a big Dutch cohort. They found the risk is not equal: people with maternal-uniparental-disomy PWS have far more psychiatric illness than deletion-type. Their numbers turned the 1994 story into a risk profile, so the 2011 paper now guides screening.

Mansell et al. (2002) followed the same idea but added time. They showed toddler style—hyper versus shy—predicts later psychosis or mood disorder. This extends the 1994 cross-section labels into a developmental road map.

Wilkinson et al. (1998) zoomed in on the psychotic bucket and gave it a clearer name: cycloid psychosis. They also told doctors to think about lithium, moving from description to treatment.

You can still use the three buckets as a quick bedside lens. If a teen with PWS is raging, think explosive-oppositional and track triggers. If voices or odd beliefs appear, remember cycloid psychosis and consult psychiatry sooner. Match the bucket to the genetic subtype from Sinnema et al. (2011) for a sharper risk picture.