Depression is an affective mental health disorder that involves feelings of sadness and depressed mood that can exist for several months or years. Antidepressants, medicines that physicians prescribe to treat depression, boost brain-communicating chemicals known as neurotransmitters, which increases communication among neurons or nerve cells in the brain. Antidepressant drugs are categorized according to which chemical(s) that they act on in the brain; specifically, the neurotransmitters affected by antidepressants are norepinephrine, dopamine and serotonin. Thus, a physician will select from these different types to treat an individual's depression.
According to Medicine Net, selective serotonin reuptake inhibitors (SSRIs) are the most prescribed type of antidepressants and produce less side effects than the older medications. They work by increasing serotonin; specifically, they inhibit the reabsorption of serotonin so that more serotonin is present to elevate, affect and promote positive feelings. Examples of this classification are Lexapro, Zoloft, Paxil and Prozac.
Serotonin and norepinephrine reuptake inhibitors (SNRIs) stop the reabsorption of norepinephrine and serotonin and as a result these neurotransmitter levels decrease at a slower rate, which helps to stabilize mood. Sample medications of this type include Effexor, Cymbalta and Pristiq. These antidepressants produce fewer side effects in comparison to older groups of medications.
MAOIs and Tricyclics
The last two categories of antidepressants, MAOIs and tricyclics, are the old generation of antidepressants. Monoamine oxidase inhibitors, or MAOIs, were discovered in 1952, however, they are not used frequently today because of the seriousness of their side effects and interactions with other medications and food. These drugs inhibit the enzyme, monoamine oxidase, which then increases levels of the neurotransmitters. Examples of MAOI's are Nardil, Parnate and Marplan.
Tricyclics drugs inhibit the reabsorption of all three discussed neurotransmitters in the brain--serotonin, norepinephrine and dopamine. Unfortunately, this group is similar to MAOIs in that it, too, is an older antidepressant and has many serious side effects; for example, an individual's blood pressure and heart rate can be affected. Some sample brands include Adaptin, Elavil, Norpramin, Endep and Sinequan.