The topographies and operant functions of challenging behaviours in fragile X syndrome: A systematic review and analysis of existing data

Background Challenging behaviour, such as self-injury and physical aggression, is an issue of concern regarding a high proportion of individuals with fragile X syndrome. The aim of this review was to provide a comprehensive overview of the topographies and operant functions of challenging behaviours within the syndrome.Method Five electronic databases were searched, identifying 18 manuscripts. Overall proportions of individuals with particular topographies of behaviour, or behaviour serving different functions, were calculated.Results Across all participants, biting was the most common form of self-injury for males but not females. A pattern of behavioural function was observed, characterised by high levels of social-negative reinforcement, such as escape from demands.Conclusion The existence of within-syndrome biases in the manifestation of behavioural challenges is supported by our review.