Stress, depression, and the immune system.

The major neurobiologic processes associated with stress have been observed in depression, and a consideration of the effect of stress on the immune system may provide further understanding of the biology of depressive disorders. A series of studies investigating stress-induced alterations of the immune system demonstrate that stress-induced modulation of immunity is complex and involves a range of neurobiologic mechanisms. Altered immune system measures do not appear to be a specific biologic correlate of major depressive disorder but may occur in subgroups of depressed patients.