The literature on challenging behaviour is large, with heavy emphasis on behavioural approaches. In recent years more attention has been given to the effect of psychiatric illness on the behaviour of people with intellectual disability. However, theoretical differences between disciplines can lead to one or other approach dominating the assessment process. Increasingly, functional assessment is receiving attention as an assessment approach by both psychiatrists and psychologists. When used properly it can give a holistic overview of the individual and their behaviour, allowing a team approach to assessment and treatment that ensures the consideration of all possible psychiatric/medical/behavioural/environmental possibilities (a bio-behavioural model) in the aetiology and maintenance of challenging behaviour. This case study illustrates the effectiveness of teamwork in this area using functional assessment as a tool. The case also illustrates the possible futility of such comprehensive assessments of challenging behaviour in the absence of appropriate resources to implement the recommendations of such an assessment.
