Adolescents with learning disability who have mental health problems often attract multiple diagnostic labels. The accretion of complexity in such instances increases with the number of diagnostic categories applied. We describe two case reports of adolescents with learning disability who developed acute psychiatric illnesses. We highlight the difficulties inherent in formulating such individuals’ problems. We also illustrate the difficulties in diagnosis in this population, the complexity of therapeutic interventions available and the particular need for consideration of the impact upon the young person and their family of diagnosing a psychiatric illness in addition to the learning disability. In our opinion, there may sometimes be a need for a highly specialized service for such individuals. However, much can be achieved by general child and adolescent mental health teams.