Antipsychotic drugs, lithium, carbamazepine, and abnormal diurnal weight gain in psychosis.

Diurnal weight gain was abnormal among 149 institutionalized chronically psychotic patients. We weighed patients weekly for 3 weeks at 7 A.M. and 4 P.M. and then normalized the diurnal weight gain (NDWG) as a percentage by subtracting the 7 A.M. weight from the 4 P.M. weight, multiplying the difference by 100, and dividing the result by the 7 A.M. weight. The NDWG was 2.026% +/- 1.399% for patients and 0.511% +/- 0.351% for normals. The NDWG related (Spearman rho = 0.328, p less than 0.0001) to chlorpromazine equivalent dose. The absence of lithium and carbamazepine, lithium alone, carbamazepine alone, and the combination of lithium and carbamazepine did not alter NDWG. Our data suggest that antipsychotic drugs may contribute to abnormal weight gain in chronic psychosis but that lithium and carbamazepine do not.