Frequency of and determinants for psychotropic drug use in an institution for the mentally retarded.

The frequency of psychotropic and anticonvulsant drug use in 168 institutionalised mentally retarded adults was studied. Use of neuroleptics and anticonvulsants was more frequent and use of hypnotics and antidepressants less frequent than in the general population. Neuroleptics were given to 49% of the population. Clients with no psychiatric diagnosis consumed less neuroleptics than those with such a diagnosis, and there was a non-significant trend for those with a more serious diagnosis (e.g. schizophrenia) to take a higher dosage. The degree of disruptive behaviour and the availability of a physician were related to dosage of neuroleptics. The various psychiatric diagnoses given could explain only a small proportion of the variance in dosage.