According to Medline Plus, depression is a serious mental illness that affects over 20 million Americans. Depression causes the following symptoms: sadness, lack of interest, weight changes, troubles sleeping, lethargy, feeling hopeless or worthless and thoughts of suicide or death. Fortunately, depression can be effectively treated by antidepressant medications according to Medline Plus.
SSRIs
According to the Mayo Clinic, selective serotonin reuptake inhibitors (SSRIs) help to relieve symptoms of depression by blocking the neurotransmitter serotonin from being reabsorbed into the brain cells. Increased serotonin levels enhance neurotransmission, which improves moods. SSRIs were approved by the Food and Drug Administration (FDA) to treat depression; however, they cause the following side effects: nausea, diarrhea, agitation, rashes, insomnia, drowsiness, weight gain and agitation, according to the Mayo Clinic. The most common SSRI is Prozac.
SNRIs
Serotonin and norepinephrine reuptake inhibitors (SNRIs) increase the levels of serotonin and norepinephrine by reducing their reabsorption into brain cells, according to the Mayo Clinic. Like SSRIs, the increased levels of serotonin and norepinepherine can improve an individual's mood. SNRIs are also approved by the FDA to treat depression and can be listed under the brand names of Effexor and Cymbalta, according to the Mayo Clinic. In addition to the same side effects as SSRIs, SNRIs also have the following: constipation, tremors, vision impairments and sexual dysfunction.
MAOIs
According to the Mayo Clinic, monoamine oxidase inhibitors (MAOIs) were the first type of antidepressants and date back to the 1950s. MAOIs prevent the enzyme monoamine oxidase from metabolizing the neurotransmitters dopamine, norepinephrine and serotonin in the brain, which keeps their respective levels high and improves an individual's mood, according to the Mayo Clinic. MAOIs have been approved by the FDA and are available under the following brand names: Emsam, Marplan, Parnate and Nardil.
MAOIs are typically used after individuals have already tried SSRIs and SNRIs because the side effects are severe. In addition to the same side effects as SSRIs and SNRIs, MAOIs also have the following side effects: decreased urine, low blood pressure, muscle twitching, trembling, lightheadedness, and fatigue.
TCAs
Tricyclic antidepressants (TCAs) reduce the reabsorption of serotonin, norepinephrine and dopamine into the brain cells, according to the Mayo Clinic. High levels of serotonin, norepinephrine and dopamine can improve an individual's mood. TCAs have been approved by the FDA and are available under the brand names of Vivactil, Norpramin and Sinequan. In addition to the same side effects as SSRIs, SNRIs and MAOIs, TCAs also have the following side effects: disorientation, urinary retention, increased heart rate, sensitivity to sunlight and increased appetite, according to the Mayo Clinic.
