Young People With and Without Intellectual Disability Accessing Mental Health Services: Evaluating Psychosocial Functioning Outcomes Using Electronic Health Records

Background There is growing recognition that many young people (<18 years) with intellectual disability (ID) may benefit from psychosocial support provided by mental health services, yet intervention outcomes have not been robustly evaluated. Method Data from 1986 episodes of care for young people with ID and 3968 matched episodes for those without ID were extracted from electronic health records of the South London and Maudsley NHS Foundation Trust (2001–2023). Psychosocial functioning was assessed using the Children's Global Assessment Scale (CGAS). Results ID frequently co‐occurred with other neurodevelopmental conditions and behavioural difficulties (prevalence > 50%). CGAS scores at service entry positively predicted CGAS scores at discharge; however, this association weakened in the presence of ID and co‐occurring pervasive developmental disorders or hyperkinetic disorders. ID was associated with lower CGAS scores at discharge than those without ID. Within the ID group, young people with severe/profound ID and comorbidities demonstrated greater rates of improvement than those with severe/profound ID only. 20% of young people with ID showed clinically significant improvement at discharge (reliable change index ≥ 1.96). Despite this improvement, 80% of the same group continued to experience substantial impairment (CGAS < 61). Conclusions Most young people with ID remained substantially impaired at discharge, highlighting the complexity of their needs and the importance of sustained, targeted support. Further research should examine specific intervention types and treatment trajectories in this population.