What does Sasha mean? Sasha [sasha] as a girls' name (also used less regularly as boys' name Sasha) is pronounced SAH-shah. It is of Russian and Greek origin, and the meaning of Sasha is man's defender. Short form of Alexander. The -sha ending may not be feminine in Russia, though it is in America. Associated with: russian, greek, defender.
Depression increases your risk of a number of diseases and other conditions by, for example, increasing levels of stress hormones such as cortisol or adrenaline. Depression can affect the immune system, making it harder for your body to fight infection. Vaccinations are even less effective in people with depression.
A possible adaptive explanation to this paradox is the immune system may become over active in response to infection and glucocorticoids are employed to calm it down (Sapolsky). Depression as a stress response would appear to be a significant failure of adaptation. However it may be argued the purpose of mood, and by implication depression, is part of a mechanism whereby the brain can register rewards and punishment (Barondes). Rewards induce good feelings and punishment induces bad feelings.