Excessive water drinking behavior in autism

The aim of this study was to determine the incidence of polydipsia in 49 au tistic children, and also the influence of psychotropic drugs and residenti al factors on water drinking behavior, as compared with in 89 mentally reta rded children, in schools for mentally handicapped children in Fukui prefec ture. Questionnaires were used to detect polydipsia and to assess the sever ity of the water drinking behavior in the autistic children and mentally re tarded children. The incidence of polydipsia in the autistic children tende d to be higher (P = 0.074) than that in the retarded children. The severity of water drinking behavior was significantly higher in autism (P = 0.022) than in mental retardation. The majority of the autistic children with poly dipsia had been taking no psychotropic drugs. The incidence of polydipsia s howed no significant difference between two residential situations, i.e. 'n ot at home' and 'at home'. The present study suggests that polydipsia or ex cessive water drinking behavior occurs more often in autism than in mental retardation, possibly due to some intrinsic factor in autism itself. (C) 19 99 Elsevier Science B.V. All rights reserved.