Final answer:
Selective serotonin reuptake inhibitors (SSRIs) affect the brain chemical called serotonin and are commonly used to treat depression.
Step-by-step explanation:
Selective serotonin reuptake inhibitors (SSRIs) affect the brain chemical called serotonin and are commonly used to treat depression. They work by blocking the reuptake of serotonin, increasing its levels in the central nervous system. Examples of SSRIs include Zoloft, Paxil, and Prozac. These medications have fewer anticholinergic side effects compared to other antidepressants, but caution should still be exercised when taking them in combination with other drugs that affect serotonergic systems.