Glucose-induced increase in memory performance in patients with schizophrenia

Previous investigations have found that increasing circulating glucose availability can increase memory performance in rodents, healthy humans, and individuals with dementia of the Alzheimer's type. In this study, patients with schizophrenia, healthy control subjects, and controls with bipolar affective disorder were tested using double-blind treatment with either 50 g anhydrous dextrose plus 4 mg sodium saccharin (for "taste") or 23.7 mg saccharin alone, followed by cognitive testing on a complex battery. At this glucose dose, verbal memory performance on a paragraph recall task was increased during the glucose condition relative to the saccharin condition in the patients with schizophrenia; this effect was not detected in either the psychiatric or normal controls. The results provide preliminary support for the hypothesis that memory performance can be improved in patients with schizophrenia by increasing circulating glucose availability and suggest the importance of further evaluation of therapeutic manipulations of glucose availability.