Earlier studies made at this laboratory showed that the injection of glutathione improved the abnormal metabolism of keto acids that occurs in psychoses and also improved the clinical status of patients with manic-depressive or schizophrenic psychoses.1 It was considered desirable to study further this apparent relation between clinical condition and state of keto acid metabolism. Earlier work had shown that giving thiamine, a vitamin essential to the oxidation of keto acids, did not ameliorate the chronic psychoses under consideration here, and hence it was decided (at the suggestion of Dr. W. W. Westerfeld) to study the action of thioctic acid, the other vitamin concerned in the utilization of the keto acids. An additional reason for studying thioctic acid concerned its sulphur content: Some sulfur-containing compounds inactivate sympathomimetic amines, as shown by Schroeder et al.,2 and there is reason to suspect that some symptoms of the psychoses studied in