Traditionally depression was defined as a mental illness. Acknowledgment of biopsychosocial model in modern medicine brought about a number of interdisciplinary studies. In the meantime, a number of correlations in the onset, cause and prognosis between depression and other somatic as well as mental illnesses were discovered. The research results showed that from one hand, depression could be an independent factor of the possible development of heart infarct, on the other hand it can influence the recovery process in cardiological patients. The conducted studies established some common pathways in depression and vascular diseases development. Psychoneuroimmunological research gives the data about the influence of anxiety and depression on the interleukine profile that could be a matter of further investigation of the possible links between depression and cancer diseases. The other dimension is the addiction impact on depression onset. The interrelationship between epilepsy as organic brain disease and depression is also worth of attentional. Hypercortisolemia and low-grade inflammation plays an important role both in depression and dementia. There is also a strong correlation between personality traits and depression itself and as response to unfavorable circumstances and somatic illness as well. We propose to apply to depression the principles of pathological stable circuits with the self-sustained reverbation engram chains mechanisms. All these data calls for consideration of depression as an interdisciplinary phenomena.