Skeletal status in mentally retarded patients on anticonvulsive therapy

X-ray densitometric measurement of radius mineral content and radiogrammetry of the cortical index of the second metacarpal were made on 644 institutionalized mentally retarded males and females, 224 of whom had received long-term anticonvulsant drug treatment. Analysis of variance of radius mineral content and metacarpal cortical index indicated that values for mentally retarded persons are not significantly different from the normal-for-age values. Radius density among anticonvulsant males, however, was significantly lower than that of non-anticonvulsant males in four out of five age groups. Among females the anticonvulsant patients were not significantly lower in radius density than the non-anticonvulsant females. Similar trends were evident in cortical indices of the second metacarpal: Two out of five age groups of anticonvulsant males were significantly lower than non-anticonvulsant males, while only one of five age groups of anticonvulsant females was significantly lower than non-anticonvulsant females. The effects of diphenylhydantoin and phenobarbital are similar in their adverse effects on bone growth and development.