The hippuric acid excretion test (after benzoate administration) has been used by previous workers, with the general result that it affords a reasonably accurate and satisfactory test for determination of parenchymatous hepatic damage and of various hepatic involvements. The test is also known to be indicative of hepatic disorder, even where no clear clinical signs of hepatic or renal derangements are observable. A series of 67 cases of mental disorder has been examined by the test, 45 of which belonged to the schizophrenic group; 18 of these were classed as catatonics. The average value of hippuric acid eliminated in the non-catatonic schizophrenic group, expressed in terms of benzoic acid, in 4 hours after administration of 6 grm. of sodium benzoate, was 3.4 grm. with an average deviation from the mean of ± 0.4 grm. This value agrees well with the values obtained by previous workers for normal cases having no hepatic damage. The average value of hippuric acid eliminated under the same conditions by catatonic patients was 2.2 grm. with an average deviation from the mean of ± 0.5 grm. All the catatonic patients studied, without exception, showed a diminished ability to excrete hippuric acid at a normal rate. It is inferred that a metabolic disturbance of the liver affecting benzoic acid detoxication may be a characteristic feature of catatonic patients.

Work on benzoic acid detoxication in catatonic patients before and after various shock treatments for schizophrenia is in progress.