Dual Diagnosis

Dual diagnosis refers to the co-occurrence of intellectual disability (ID) and mental illness. Individuals with ID may also have epilepsy, sensory limitations, mobility issues, and other medical conditions, resulting in many more diagnoses than the two encompassed by the term dual diagnosis. The term dual diagnosis has a different meaning in the mental health field, where it refers to the co-occurrence of substance abuse and psychopathology. The presence of a psychiatric disorder for an individual with ID can have negative effects on daily functioning, educational and vocational performance, and family and social relationships. This entry discusses the prevalence, causes, diagnosis, assessment, and treatment of dual diagnosis.