Biomarkers of Depression Associated with Comorbid Somatic Diseases.

Depression is heterogeneous clinical entity with different clinical symptoms, that imply diverse biological underpinning, different molecular substrates and pathways. Besides different psychiatric comorbidities, depression is frequently interrelated with somatic diseases. Multi-morbidities, i.e. somatic diseases associated with depression, reduce quality of life, worsen clinical picture and increase mortality. The most frequent somatic diseases co-occurring with depression are cardiovascular and metabolic diseases. Vulnerable individuals will develop depression, and the goal in modern research and in precision/personalized medicine is to determine vulnerability factors associated with development of depression and to find easy available biomarkers of depression, especially comorbid with somatic diseases. This mini-review aimed to describe the latest published data (from 2015-20120) considering biomarkers of depression related to somatic diseases. Biomarkers related to inflammatory processes, atherosclerosis, imbalance of the hypothalamic-pituitary-adrenal axis, autonomic nerve system, sympathetic and parasympathetic nervous system, heart rate variability and endothelial dysfunction could improve the understanding of the underlying biological mechanisms of the common pathways of depression comorbid with somatic diseases. These targeted biomarkers might be used to reduce the symptoms, improve the treatment of these interrelated diseases, and decrease the morbidity and mortality.