Drug class

SSRIs

Also called Selective serotonin reuptake inhibitors

First-line antidepressants — also used for anxiety, OCD, panic, and PTSD.

How it works

SSRIs slow how quickly the brain reabsorbs serotonin. More serotonin stays available between nerve cells, which over a few weeks tends to lift mood and reduce anxiety.

What it treats

Major depressive disorder, generalized anxiety, panic disorder, OCD, PTSD, PMDD.

Common side effects

Nausea or stomach upset (usually fades in 1–2 weeks), insomnia or drowsiness, sexual side effects, sweating.

Worth knowing

Black-box warning for increased suicidal thoughts in adolescents and young adults. Don't combine with MAOIs. Stopping abruptly can cause discontinuation symptoms — taper with a prescriber.