This is a report of a service improvement pilot project undertaken at an inpatient autism service for adults with intellectual disabilities and severe challenging behaviours. Within the service, a key facet of the care pathway was the use of a biopsychosocial case formulation. Formulation meetings were led by psychology and involved a full multidisciplinary team and external representation. However, routine invitation of patients was not appropriate due to anxiety and complex communication difficulties. Therefore, the service was looking for alternative ways to incorporate the voices of patients into formulation. This report presents the case studies of four individual patients who were chosen because together they were indicative of the patient profile across the service. The study has demonstrated that it is possible to include patients' voices in their psychological formulation. For those with mild intellectual disabilities and mild autism spectrum disorder, this has been simple and extremely fruitful. For those with severe intellectual disability and severe autism spectrum disorder this has been more resource intensive and the results have been more tentative. Despite this, it has been demonstrated that it is possible to include the voices of all patients to some extent.