Abnormal diurnal weight gain among institutionalized patients with manic-depressive spectrum disorders.

We found diurnal weight gain to be abnormal among 41 institutionalized patients with manic-depressive spectrum disorders. They were weighed at 7 AM and 4 PM weekly for three weeks. We normalized the diurnal weight gain (NDWG) as a percentage by subtracting the 7 AM weight from the 4 PM weight, multiplying the difference by 100, and then dividing the result by the 7 AM weight. NDWG was 2.216 +/- 1.513 percent for the study population, .631 +/- .405 percent for 16 young, newly admitted controls, and .511 +/- .351 percent for 29 normals. Abnormal NDWG may be an additional feature of manic-depressive spectrum disorders.