Several different types of antidepressants work differently to address symptoms of depression. As described by the National Institute of Mental Health, antidepressants help to maintain the proper balance of chemicals, or neurotransmitters, in the brain, helping to control a person's mood. Different antidepressants impact different neurotransmitters, including serotonin, dopamine, and norepinephrine.
According to the U.S. Food and Drug Administration, antidepressants are effective in treating depression immediately in 60 to 70 percent of cases. However, they note that individuals must take their medication for a few weeks in order to see treatment gains. The National Institute of Mental Health reported that individuals who do not respond to the first antidepressant they are prescribed often see improvements when they try a new medication or add a second medication to their regimen.
Selective Serotonin Reuptake Inhibitors (SSRIs)
As reported by the National Institute of Mental Health, the most commonly used antidepressants are SSRIs. These include Prozac or fluoxetine; Celexa or citalopram; Zoloft or sertraline; Paxil or paroxetine; and Lexapro or escitalprolam. According to the U.S. Food and Drug Administration, these medications act to enhance serotonin levels in the brain.
Serotonin and Norepinephrine Reuptake Inhibitors (SNRIs)
SNRIs that are commonly used include Effexor, or venlafaxine, and Cymbalta, or duloxetine. According to MayoClinic.com, these drugs work to increase serotonin and norepinephrine levels in the brain. They are similar to SSRIs, but impact two neurotransmitters in the brain. As noted by the National Institute of Mental Health, common side effects of both SSRIs and SNRIs include headache, difficulty sleeping, feeling drowsy, feeling restless, nausea, and some sexual problems.
Other Types of Antidepressants
In the past, antidepressants such as tricyclics and monoamine oxidase inhibitors were used; however, the newer antidepressants, such as SSRIs and SNRIs, have fewer side effects and tend to be prescribed more frequently, according to the National Institute of Mental Health. MAOIs have some significant side effects and require that individuals stick to a strict diet to avoid drug interactions, and tricyclics have additional side effects including dry mouth and constipation. Some examples of MAOIs listed by the U.S. Food and Drug Administration include Nardil, or phenelzine, and Parnate, or tranylcypromine. Tricylics include Elavil or amitriptyline and Tofranil, or imipramine. Although the SSRIs and SNRIs are more commonly used, some of the older antidepressants still work better for certain individuals, the National Institute of Mental Health notes. Another type of antidepressant, Wellbutrin, or bupropion, affects the neurotransmitter dopamine, and is becoming more common in its usage.
