Investigations carried out in the past into the steroid hormone excretion rate of mental patients have been limited to the quantitative determination of the total compounds. Assay of neutral 17-ketosteroids in particular, has revealed no significant difference in the excretion rates of schizophrenics from that of normal controls (Leth Pedersen, 1947; Lingjaerde and Lierasylet, 1949 et al). Pincus (1943) has studied the diurnal excretion pattern of 17-ketosteroids in normal persons; a different pattern was shown to occur in some schizophrenics (Reiss, Hemphill, Gordon and Cook, 1949). Some schizophrenic patients also show considerably greater fluctuations in the 24-hour excretion rate than normal persons (Reiss et al., 1949), these fluctuations disappearing after successful treatment of the patients (Reiss, 1952). An increased percentage of excreted 3 β-hydroxy-17-ketosteroids has recently been reported (Mittelman, Romanoff, Pincus and Hoagland, 1952) in schizophrenics compared with normal people, the total ketosteroid excretion rate being found similar in both groups. Increased β-ketosteroid excretion rate was also seen by Reiss, Hemphill, Gordon and Cook (1949), during depressive phases in a state of manic depressive psychosis.