===Biological=======Monoamine hypothesis====Most antidepressant medications increase the levels of one or more of the monoamines—the neurotransmitters serotonin, norepinephrine and dopamine—in the synaptic cleft between neurons in the brain.
Konkretneje, depresija lahko sledi takšnim dogodkom, vendar pa se zdi bolj verjetno, da se pojavi pri ljudeh z enim ali dvema kratkima alelama gena 5-HTT.