Depression is not simply feeling down for a day or two; it is a major disorder that is experienced by many each day. Sometimes, psychotherapy alone is not enough to prevent or treat a depressive disorder. Antidepressants, or medicines that treat depression, boost brain-communicating chemicals known as neurotransmitters; this, in turn, helps communication among neurons or nerve cells in the brain. The neurotransmitters affected by antidepressants are dopamine, norepinephrine and serotonin. Antidepressant drugs are categorized according to which chemical(s) that act on in the brain.
MAOIs & Tricyclics
MAOIs and tricyclics are the old generation of antidepressants. Monoamine (or monamine) oxidase inhibitors, or MAOIs, are not used frequently because of the seriousness of their side effects, their interactions with other medications and with food. These drugs inhibit the enzyme monoamine oxidase, which then increases levels of neurotransmitters. Examples of some sample MAOI's are Nardil, Parnate, EMSAM and Marplan.
Tricyclic drugs inhibit the re-absorption of all three discussed neurotransmitters in the brain, that is, serotonin, norepinephrine and dopamine. Unfortunately, this group is similar to MAOIs in that it, too, is an older antidepressant, and also 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 Sinequan and Ludiomil.
SSRIs & SNRIs
A type of antidepressant that is widely prescribed is known as selective serotonin reuptake inhibitors (SSRIs). This group of drugs increases serotonin; specifically, they inhibit the re-absorption of serotonin so that more is present to elevate affect and promote positive feelings. Examples of this classification are: Lexapro, Zoloft, Paxil, Prozac and Pexeva.
Alternately, serotonin and norepinephrine reuptake inhibitors (SNRIs) are drugs that stop the re-absorption of norepinephrine and serotonin, and as a result, these neurotransmitter levels are not decreased in the brain, which helps to stabilize mood. Examples of this type include Effexor, Cymbalta and Pristiq. These two classes tend to produce fewer side effects than the older medication groups (MAOIs & Tricyclics).
NDRIs
Norepinephrine and Dopamine Reuptake Inhibitors (NDRIs) alleviate depression by inhibiting the reabsorption process of these two neurotransmitters. The result is that norepinephrine and dopamine levels are increased, which lessens the symptoms of depression. However, there is only one NDRI available today that is approved by the Food and Drug Administration---bupropion also known by the names of Wellbutrin and Zyban. It has a multi-use history; for example, it has been used to stop smoking and also has been used to treat obesity, attention deficit disorder (ADD), and seasonal affective disorder (SAD). A major side effect is that it may cause hypertension, thus, a history of cardiovascular disease may exclude one from using this drug.
