After the publication of data on the detection of insulin in brain tissue, interest in studying the role of insulin in the central nervous system (CNS) and changes in the central nervous system in diabetes mellitus increased sharply. In patients with diabetes, a high frequency of mental disorders has been established. Complications of the nervous system in children whose mothers were pregnant with diabetes during pregnancy are described in literature. The role of insulin in the development and differentiation of neurons, potentiation of synaptic activity, the exchange of catecholamines, transcription of genes in nerve cells has been identified, which allows a better understanding of the mechanism of diabetic encephalopathy. This review analyzes the results of experimental studies of the central nervous system in diabetes.