Dual diagnosis: developmental disability complicated by mental illness.

When mental retardation is complicated by mental illness, the clinical result is "dual diagnosis." Though recognized as such only since the 1970s, these patients have long been the subset of the developmentally disabled most resistant to integration into the community. The maladaptive behavior or mental illness often prevents training for the retardation or other developmental disability. Because these patients are no longer placed in the back wards of state institutions, the modern expectation is that even this most difficult group can be influenced by positive behavior support directed by a psychologist and medication treatment programs prescribed by a psychiatrist. In addition, program specialists structure the work, play, and learning environment of the patients. These activities, living conditions, and peer relationships will form a dynamic interaction with the behavior therapy and the medication. The challenge of adapting to this interaction is met by an interdisciplinary team. Subject to bizarre behavior and difficult to diagnose and treat, patients with both mental retardation and mental illness are best directed to providers trained for these patients.