A quarter of People with Intellectual Disabilities (PwID) have epilepsy compared with 1% of the general population. Epilepsy in PwID is a bellwether for premature mortality, multimorbidity and polypharmacy. This group depends on their care provider to give relevant information for management, especially epilepsy. There is no research on care status relationship and clinical characteristics of PwID and epilepsy.

Explore and compare the clinical characteristics of PwID with epilepsy across different care settings.

A retrospective multicentre cohort study across England and Wales collected information on seizure characteristics, intellectual disability severity, neurodevelopmental/biological/psychiatric comorbidities, medication including psychotropics/anti-seizure medication, and care status. Clinical characteristics were compared across different care settings, and those aged over and younger than 40 years.

Of 618 adult PwID across six centres (male:female = 61%:39%), 338 (55%) received professional care whereas 258 (42%) lived with family. Significant differences between the care groups existed in intellectual disability severity (P = 0.01), autism presence (P < 0.001), challenging behaviour (P < 0.001) and comorbid physical conditions (P = 0.008). The two groups did not vary in intellectual disability severity/genetic conditions/seizure type and frequency/psychiatric disorders. The professional care cohort experienced increased polypharmacy (P < 0.001) and antipsychotic/psychotropic use (P < 0.001/P = 0.008).

The over-40s cohort had lower autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD) comorbidity (P < 0.001/P = 0.007), increased psychiatric comorbidity and challenging behaviour (P < 0.05), physical multimorbidity (P < 0.001), polypharmacy (P < 0.001) and antipsychotic use (P < 0.001) but reduced numbers of seizures (P = 0.007).

PwID and epilepsy over 40 years in professional care have more complex clinical characteristics, increased polypharmacy and antipsychotic prescribing but fewer seizures.