Tricyclic Antidepressants (TCA’s)
(e.g., Elavil, Pamelor, Norpramin)

Function: TCA’s block the reuptake of the neurotransmitter norepinephrine (NE), making more NE available to the brain. These drugs also help reduce the reuptake of serotonin by decreasing the number of serotonin receptors on the neurons that release it. Continual use of TCA’s has been shown to reduce relapse rates of depression.

Negative Side Effects: People taking TCA’s may experience sweating, drowsiness, dry mouth, blurred vision and risk of overdose. TCA’s are also slow-acting.

Monoamine Oxidase Inhibitors (MAO inhibitors)
(e.g., Parnate, Nardil)

Function: MAO inhibitors prevent the breakdown of NE by inhibiting the enzyme MAO.

Negative Side Effects: MAO inhibitors have known lethal side effects when combined with certain foods, including red wine, beer, shellfish and aged cheese, or with narcotics or high-blood-pressure-reducing drugs. They can also produce sexual dysfunction, heart problems, and insomnia.

Selective Serotonin Reuptake Inhibitors (SSRIs)
(e.g., Prozac, Paxil, Zoloft)

Function: SSRIs, like their name describes, selectively inhibit the reuptake of serotonin so that there is still enough in the body to keep a person from becoming depressed. As with TCA’s, continual use can reduce relapse rates. SSRIs are the most commonly known antidepressants, the ones that you may have seen advertisements for. These drugs are often prescribed for less severe cases of depression. They are the type of antidepressant that are being prescribed more and more frequently.

Negative Side Effects: SSRIs have a tendency to produce nausea, insomnia and nervousness, sexual dysfunction and muscle tenseness. There is also a theory that Prozac may lead to suicidal thoughts and behavior [Teicher, M., et al, 1990] clearly counteracting the positive effects of antidepressants.

Atypical Antidepressants
(e.g., Serzone, Efexor, Trazadone, and Wellbutin)

Function: Atypical antidepressants influence the amounts of both NE and serotonin that are being broken down or reuptaken. Some of these drugs also act on dopamine levels, and can act as stimulants as well as antidepressants [Seligman, M., et al, 2001]. These drugs are relatively new on the market.

Negative Side Effects: These drugs can produce vertigo, constipation, dry mouth and insomnia. Certain of the atypical antidepressants, such as Efexor, have created an increased risk of seizures in some individuals.

There is also a general negative side effect of these drugs, which is that once they are stopped a person has a high chance for relapse of depression. This has led many researchers to strongly consider psychological therapy, or a combination of drugs and therapy, as having greater potential for treating the illness.