How do antidepressants work?

The most common types of antidepressants are SSRIs, SNRIs and NDRIs, which are all reuptake inhibitors They increase levels of certain chemicals, such as serotonin, norepinephrine and dopamine, within the brain by preventing them from being absorbed or taken up by neurotransmitters, according to WebMD.

While most antidepressants work in this way, others increase levels of certain chemicals by blocking the effects of enzymes that break down seratonin, norepinephrine and dopamine, says WebMD. These drugs are known as monoamine oxidase inhibitors or MAOIs. All antidepressants work to increase levels of select chemicals within the brain in an effort to elevate and stabilize mood and emotion, says Dr. Craig Freudenrich for HowStuffWorks.