Survey of diurnal weight gain and urine volume in chronic schizophrenia.

We found diurnal weight gain to be abnormal among 39 chronic schizophrenic patients. The patients were weighed and urine samples obtained weekly for three weeks at 7 a.m. and 4 p.m. We normalized the dirunal 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 then dividing the result by the 7 a.m. weight. NDWG was 2.075 +/- 1.331% for the 38 study patients, .631 +/- .405% for 16 acutely psychotic controls and .511 +/- .351% for 29 normals. Seventy-seven percent of the study patients had abnormal NDWG values and 62% were polyuric. NDWG related to urine volume (n = 39, r = .356, p = .026) with the variability in urine excretion explaining 13% of the variability in NDWG. We discuss factors that may have contributed to our findings.