Do SSRIs Like Zoloft Really Boost Serotonin? Sertraline (Zoloft) is one of the most commonly prescribed antidepressants, classified as an SSRI — selective serotonin reuptake inhibitor. But here’s something often overlooked: SSRIs don’t create serotonin. Instead, they block serotonin from being reabsorbed at the nerve synapse, leaving more available in the brain. The theory is that this extra serotonin helps regulate mood, calm anxiety, and ease OCD or PTSD symptoms. But there’s controversy. Over