How do antidepressants like Prozac and Zoloft (sertraline) work?

SSRIs. These are medications that prevent the reuptake of serotonin, a chemical messenger that plays a role in brain activity including depression/anxiety. By doing this, the effective amount of serotonin available will increase. Adjustments take place over a period of time and that is why a person needs to take the medication daily for many weeks before effect is seen. Good luck!