How SSRIs work

Serotonin is one of many chemical messengers in the brain called neurotransmitters. Neurotransmitters carry signals between nerve cells in the brain, called neurons.

After carrying a signal between brain cells, serotonin usually is taken back into those cells, a process called reuptake. But SSRIs block this process. Blocking reuptake makes more serotonin available to help pass messages between brain cells. SSRIs are called selective because they mainly affect serotonin, not other neurotransmitters.

SSRIs may be used to treat conditions other than depression, such as anxiety disorders.