The exact mechanism that allows Zoloft to combat depression, anxiety and OCD is still not completely understood, can i purchase lyrica without prescription however what researchers have noticed is that Zoloft affects the way serotonin is managed by the human body. Serotonin is part of a drug family known as selective serotonin re-uptake inhibitors (or SSRI's). SSRI's increase the level of serotonin in the brain by inhibiting (not preventing) its breakdown. And yes, while this may seem complicated it really isn't.