[Why does a person become depressed?].

Genotype, temperament, early traumas, ongoing stress as well as the their mutual, cumulative effects are factors predisposing to depression. Depressed patients often have minor structural lesions of the brain, and during the depressive state they exhibit both neurochemical abnormalities and plasticity, metabolic activity and neuroendocrinological abnormalities of the brain. For the most part, these will return to normal with the convalescence. A temperament predisposing to depression may be reflected in functional imaging studies of the brain. The depressive state is usually triggered by a negative life event.