It is commonly recognized in postwar Japan that the psychological symptoms of patients addicted to methamphetamine hydrochloride β (Methedrine) resemble very closely those of schizophrenics. In our observations also the patients addicted to methamphetamine hydrochloride displayed such symptoms as abulia, lassitude, anxiety, instability, irritability, sometimes melancholia, catatonia-like excitement, and stupor. In perception and thought, moreover, variable delusions, delusional moods, hallucinations, occasional desultory thoughts, were frequently present. From this viewpoint, biochemical investigations of the brain tissue metabolism of animals injected repeatedly with methamphetamine hydrochloride were made in comparison to that of schizophrenic patients. It was proved by Utena et al.1 that the frequent administration of methamphetamine hydrochloride to the guinea pig reduced aerobic glycolysis without impairment of respiration in the brain tissue. According to Meyerhof,2 adenosine triphosphatase and hexokinase play important roles in the glycolysis of brain tissue. This opinion was supported by