How antidepressants work

When certain chemicals in the brain (such as serotonin, norepinephrine, and dopamine) are out of balance, depression can occur. Antidepressants improve the symptoms of depression by bringing these chemicals back into balance. Because different types of antidepressants are designed to work differently, side effects associated with each type of depression medication can vary. Some of the major types of antidepressants are discussed below:

NDRIs (Norepinephrine and dopamine reuptake inhibitors) are a type of antidepressant that increases the levels of norepinephrine and dopamine by blocking their "reuptake" in the brain. Buproprion is the only antidepressant within this class of drugs approved by the FDA. Side effects may include weight loss, loss of appetite, and dry mouth.

SSRIs (Selective Serotonin Reuptake Inhibitors) are a widely used type of antidepressant. SSRIs increase serotonin in the brain by blocking "serotonin reuptake" in the brain. These types of antidepressants can cause sexual side effects (see Common Side Effects of Antidepressants).

SNRIs (Serotonin and Norepinephrine Reuptake Inhibitors) work in much the same way as an SSRI. SNRIs block the "reuptake" of both serotonin and norepinephrine. SNRIs may also cause side effects similar to SSRIs (see Common Side Effects of Antidepressants).

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