Individuals with Intellectual or Developmental Disabilities are at a high risk of developing behavioral health problems. This has a major effect on their general well-being, personal independence, productivity, quality of life and impacts family and caretakers. They are a very vulnerable group of people served by both behavioral health and developmental disability agencies. As Shriver (2001) has pointed out, historically, existing systems and services tend to be organized around these individuals with a dual diagnosis of Intellectual Disability and Mental Illness as though they have either mental illnesses or developmental disabilities- but not both. In most states, including Maryland, they face barriers to services due to lack of coordination and collaboration of service systems, gaps in research, clinical competency and training, and access to appropriate programs.

There is growing stigmatization and prejudice leading to social exclusion of these‘other dually diagnosed’ individuals. Estimates of the frequency of ‘the other dually diagnosed’ vary widely. However, about 30%-35% of persons with Intellectual Disabilities has a co-occurring psychiatric disorders per NADD, an association for persons with developmental disabilities and mental health needs. The process of deinstitutionalization of people with developmental disabilities, for example- closing of the Rosewood Center in Maryland, has increased the visibility of individuals with ‘the other dual diagnosis’ in the community. More psychiatric disorders have been observed since the closing of the Center and the community placement of the people from the center. We continue to face impediments to professional recognition of ‘the other dual diagnosis’.

“Diagnostic overshadowing” has minimized the signs of psychiatric disturbance in persons with Intellectual Disabilities. Mental illness in a person with Intellectual Disability is less debilitating than Intellectual Disability. There are funding challenges because each system expects the other to serve the people with the co-occurring Intellectual Disability and Mental Disorders. Staff are ill-equipped to provide adequate services. There is lack of qualified clinicians with training and expertise in Developmental Disability to diagnose and treat psychiatric disorders among individuals with Intellectual Disabilities.