We present a review of psychiatric associations with comorbid mental and behavioural disorders affecting people with Prader-Willi syndrome (PWS). This literature review suggests that some assumptions about psychiatric associations of PWS behaviours are unjustified (eg skin picking as OCD) and that genetic aetiology should be considered when making associations between PWS mental and behavioural disorders and psychiatric disorders in the general populationThe literature review also demonstrates the limitations of the studies in terms of small numbers, non-representativeness, and lack of replication.