The prevalence, incidence, and factors predictive of mental ill-health in adults with profound intellectual disabilities

Background: There are no previous studies of the prevalence and incidence of mental ill-health in adults with profound intellectual disabilities.
Method: In this population-based prospective cohort study, adults with profound intellectual disabilities underwent psychiatric assessment (n = 184), with further assessment after 2 years (n = 131).
Results: Point prevalence of mental ill-health was 52.2% by clinical, 45.1% by Diagnostic Criteria for Psychiatric Disorders for use with Adults with Learning Disabilities (DC-LD), 10.9% by the ICD-10 Classification of Mental and Behavioural Disorders Diagnostic Criteria for Research (1993) (DCR-ICD-10) and 11.4% by Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (2004) (DSM-IV-TR) criteria. The highest 2-year incidence rates were for affective disorders (6.1%) and problem behaviours (6.1%). Type of accommodation/support, and the number of preceding life events were predictive of incidents of mental ill-health, but age, gender, living in areas of greatest deprivation, and having special communication needs were not.
Conclusions: Mental ill-health is more commonly experienced by adults with profound intellectual disabilities than the general population, or other adults with intellectual disabilities, warranting proactive supports/interventions. Predictive factors differ, compared with the general population.