IT HAS BEEN repeatedly observed that schizophrenics do more poorly than normals on a variety of psychological performance tests. This performance impairment has often been considered to be a secondary manifestation of the illness rather than the result of some primary alteration in the central nervous system. However, a number of investigators have suggested that there may be some primary dysfunction in the arousal system and the subcortical areas that subserve arousal in the schizophrenic.1,5,14,15 On the basis of neuropharmacological, neurophysiological, and psychological evidence, Kornetsky and Mirsky7 concluded that in the schizophrenic patient there may be a malfunction in the midbrain or brain stem reticular formation. An altered arousal system could account for much of the impairment in performance seen in the schizophrenic and more specifically the impaired attention as seen in the patients inability to maintain a "set" in the reaction