Institutionalised mentally retarded in a state mental hospital.

298 institutionalised mentally retarded patients in Institute of Mental Health, Madras were studied for the aetiological factors, levels of intelligence, associated disorders and family structure and compared with 163 matched group of mentally retarded attending the outpatient services of the Institute of Mental Health. In 41% of the institutionalised the cause was unknown, 29.3% had infective aetiology, 18% formed the primary group and 6.4% were due to genetic and chromosomal factors. Statistically significant number of institutionalised were severely subnormal, had more associated disorders and poor family structure. The need for the development of exclusive residential services for the mentally retarded and community oriented approach are discussed.