The bilateral comorbidity of thesedisorders (depression aggravates the course of diabetes and vice versa) hasbeen studied [22, 23].In addition to the convincing data on the role of adeficiency in the brain-derived neurotrophic factor (BDNF) in the pathogenesisof depressive states of different etiologies, including in patients withdiabetes [24], it has been demonstratedthat the activity of NGF drops both in depression and in diabetes, which isconsidered to be an important factor that determines their comorbidity. This evidence concerns the gene BDNF and depressive disorder.