Quezi

The popularity of antidepressants is a worldwide phenomenon. These antidepressants are from Germany. Schoschie photo. CC-BY

In the past few decades, antidepressants — medicines designed to lift the mood of people who are seriously depressed — have become almost routinely prescribed. The availability of new medicines that have fewer side effects than the old standbys have been one factor in their popularity, as has been a lessened stigma about seeking prescriptions for psychotropic drugs.

Strangely, scientists don’t know exactly how antidepressants work, although their action affects certain chemicals in the brain known as neurotransmitters that include serotonin, dopamine and norepinephrine. And their effectiveness continues to be a matter of considerable study and debate. About a third of patients report that antidepressants provide no help at all, and similar numbers have reported being helped by a placebo such as a sugar pill. Overall, though, the studies show that antidepressant medications help many people — but that they provide no instant cure, and that persons suffering from depression should also look into the nonmedical alternatives such as psychotherapy. Even exercise can have an antidepressant effect for many people.

Here are some of the most common types of antidepressants:

Tricyclics or TCAs such as imipramine were the first antidepressants to be developed (in the 1950s) and are considered to be among the most effective. However, because of side effects — which include heart problems and the danger of overdosing — they are seldom used today except in cases where other antidepressants aren’t effective.

Monoamine oxidase inhibitors or MAOIs such as phenelzine and iproniazid are another older style of antidepressants that are also seen as quite effective. However, they are seldom prescribed today unless other drugs are ineffective, because of adverse interreactions not only with other drugs but also with foods including some types of cheese. Such interreactions can occur for weeks after an MAOI is taken.

Selective serotonin reuptake inhibitors or SSRIs were the first class of antidepressants to reach the mass market with the development of drugs such as fluoxetine (Prozac) and paroxetine (Paxil or Seroxat, depending on the country) in the 1980s. Today, they are usually the first antidepressant that most doctors will try on a patient. Side effects are much less than with the older class of drugs; some, such as dryness of mouth, can be a nuisance, while others, such as inhibiting sexual performance, can be a dealbreaker for some. Although they aren’t addictive, generally patients are told to avoid quitting the drugs cold turkey and instead to gradually decrease the dose taken.

Norepinephrine-dopamine reuptake inhibitors or NDRIs, the most common being bupropion (called Wellbutrin when used for depression, Zyban when used as a smoking cessation aid), work something like a slow-acting stimulant. Unlike the SSRIs, NDRIs generally aren’t used also as treatment for anxiety.

Serotonin-norepinephrine reuptake inhibitors or SNRIs such as venlafaxine (Effexor) and duloxetine (Cymbalta) are another new class of drugs. They seem to have many of the same plusses and minuses as the SSRIs even though they function differently.

Antipsychotics are medicines that were developed for treatment of mental illnesses such as schizophrenia. In recent years, makers of such drugs experimented with using them for depression, often in conjunction with a regular antidepressant. An example is aripiprazole, sold under the trademark Abilify.

There are also other classes of antidepressants that are prescribed less often than these, and occasionally drugs designed for other issues are tested to see if they are effective for depression. There also have been studies done on herbal treatments, although results have been mixed. St. John’s wort is the most popular of those.

Not all antidepressants work on all people, so doctors often have to work with patients over a period of several months to see which works best and at what dosage. Many of the antidepressants take several weeks before they are fully effective, and they sometimes suddenly become ineffective after extended use. As always, prescription drugs such as those listed here should be used only under the supervision of a doctor or other medical professional.

This article was written for informational purposes and should not be considered medical advice or used to self-treat any condition.