Type 2 diabetes mellitus, cerebral small vessel disease and depressive disorders

Patients with type 2 diabetes mellitus (T2DM) have a significantly higher risk of developing depressive disorders compared to individuals without impaired carbohydrate metabolism. In the context of population aging and the increasing prevalence of T2DM, there is an urgent need to better understand the mechanisms that determine the relationship between diabetes and brain disease. Depressive disorders and T2DM often share genetic, behavioral, and psychosocial risk factors. However, it is still unclear whether depression is associated with an increased risk of developing a wide range of cardiovascular diseases in patients with T2DM, and whether metabolic biomarkers may mediate these associations. Existing scales for assessing cardiovascular risk demonstrate insufficient accuracy in prediction, which prompts the search for new, more objective markers, one of which is arterial stiffness. Cognitive impairment and depressive disorders in T2DM are likely to have different underlying pathophysiological mechanisms. However, one of the common mechanisms may be microvascular dysfunction, namely cerebral small vessel disease (CSVD). Signs of CSVD progress linearly with the development of the condition, from the physiological state of glucose metabolism to prediabetes and T2DM, which correlates with glycemic levels even at the stage of prediabetes. There is a hypothesis that CSVD may serve as an early and determinant mechanism for the development of depressive disorders, especially among elderly patients. However, data on CSVD and arterial stiffness in patients with T2DM and comorbid depressive disorders remain limited. The aim of this review was to discuss the specifics of the relationships between T2DM, cerebral small vessel disease, arterial stiffness, and depressive disorders, as well as to analyze new trends and directions for future research. The search was conducted in Scopus, Science Direct (from Elsevier) and PubMed, including MEDLINE, databases. The keywords used were “diabetes mellitus”, “cerebral small vessel disease”, “arterial stiffness”, and “depressive disorders.” A manual search of the bibliography of publications was used to identify research results that could not be found during the online search.