The Presentation of Mental Illness in Mentally Retarded Adults

Summary A survey of 1507 mentally handicapped adults in a long-stay hospital, three-quarters of whom were severely subnormal, led to the identification of 42 (2.8 per cent of the total group) with a current typical affective illness. Non-verbal criteria were used so that such conditions could be recognized at any level. Schizophrenia could be diagnosed only on verbally expressed symptoms and was found in 27 (1.8 per cent) of the patients, none of whom was preverbal in mental level. Forty-one (2.7 per cent) had an atypical affective illness superimposed on an early childhood psychosis. Half of these patients were preverbal, so that the pattern of their illness was particularly difficult to recognize.