Developing an understanding of skin picking in people with Prader-Willi syndrome: A structured literature review and re-analysis of existing data.

A search of the PubMed and Web of Science databases for articles on skin picking in PWS was undertaken identifying case studies; trials of specific treatments; and descriptions of when skin picking occurs, what sites are chosen, and what initiates and sustains this behaviour. Published papers have also considered how skin picking might link to the PWS genotype and whether it is best considered to be part of the repetitive and ritualistic behaviours characteristic of the syndrome. To answer specific questions raised as a result of the review additional analysis was undertaken using data from our earlier population-based study of PWS. We consider this behaviour of skin picking using the framework of the Research Domains Criteria that is cross diagnostic and focuses on the identification of specific neurobiological, psychological and cognitive processes. PWS illustrates the likely interplay between different processes that first initiate and then maintain such behaviour. Treatment development depends on better understanding these mechanisms and their relative contribution to the behaviour.