Abstract
Mentally retarded Australians with emotional and behavioural disorders are seriously under-served by psychiatrists, despite such individuals being as prevalent as those with schizophrenia. These disorders have serious consequences for the individual, family and carers, and the community as a whole. In the psychiatric assessment of mentally retarded persons, a key principle is that while intellectual handicap increases vulnerability to psychiatric illness, it does not of itself cause psychopathology. A biopsychosocial framework provides a model whereby those factors which are contributing to psychopathology can be systematically elucidated. Biological factors include brain pathology associated with particular mental retardation syndromes, drug side-effects and epilepsy. Psychological factors include temperament, a history of abuse, and current life stresses. Social factors include distortions in family roles and hostel or workshop conflicts. Although clinical assessment can be challenging, and confident syndrome diagnosis is not always possible, a systematic approach to the analysis of symptoms will provide a guide to useful interventions.