Substance Index

Antidepressants are a class of psychoactive medications that treat depression and related conditions. Most antidepressants slow the reabsorption of serotonin or noradrenaline in the brain, which keeps more of it active over time. For this reason, they have no immediate effect and take weeks to work. An antidepressant is not the opposite of a "depressant" drug. The two words use "depress" in different senses: one refers to the mood disorder, and the other refers to a slower nervous system.