[Endogenous psychoses in relation to absent phenylalanine hydroxylase activity in thrombocytes].

Out of 100 psychotic patients who underwent neurobiochemical examination, in 24 cases activity of phenylalanine hydroxylase in the thrombocytes was found to be absent. 38% of these cases were susceptible to stimulation in vitro by means of folic acid derivative, without actually reaching a normal level of activity. The patients are presented first as a homgeneous group, then in the two major diagnostic divisions, and divided according to the biochemical data. An account is given of early experiences in the treatment of the more intractable cases.