The Rapid Intravenous Glucose Tolerance Test in Psychiatric Patients

Abstract

A number of reports have appeared in the literature describing abnormal glucose tolerance in various mental disorders as measured by reduction in tolerance for ingested sugar. Carbohydrate metabolism is extremely complex and is interrelated with the fat and protein metabolism as well as with mineral metabolism. The measurement of one particular phase of carbohydrate metabolism by observation of the manner in which the organism utilizes a given amount of sugar gives rise to speculation that changes are occurring throughout the body, both within the cells and in the extracellular fluids, influencing all the metabolic processes in a chain reaction type of circuits and cycles. To date, no means of measuring total metabolism has been devised, and we must content ourselves with the piecemeal type of approach, subject to our limited techniques, and attempt to draw workable conclusions.The relationship between carbohydrate metabolism and mental illness became apparent first in 1928, when Manfred Sakel observed that long periods of insulin-induced hypoglycemia influenced mental symptoms. The exact nature of these changes is not known, but it is established that glucose is the only source of metabolic fuel utilized by the cells of the central nervous system, and alterations in its availability may act as a