Get a basic understanding of antidepressants. Learn what antidepressants are and how they work.

Learn more about the most common antidepressant prescription medications.

Depression is not something you can just "snap out of." It's caused by an imbalance of brain chemicals, along with other factors. Like any serious medical condition, depression needs to be treated. Explaining Medication offers information designed to help you get the facts and individual dealings with depression, clinically known as major depressive disorder.

What are antidepressants?

Antidepressants are drugs that relieve the symptoms of depression. They were first developed in the 1950s and have been used regularly since then. There are several different types, but this leaflet will concentrate on the older "tricyclic" antidepressants and the newer "SSRIs" (Selective Serotonin Reuptake Inhibitors). These two types account for 95% of antidepressants prescribed. There is a newer group called "SNRIs" (Serotonin and Noradrenaline Reuptake Inhibitors), but these are not as widely-used.

How do they work?

There are almost thirty different kinds of antidepressants available today. They all work by altering the way in which certain chemicals work in our brains. These chemicals are made by our body and are called neuro-transmitters.

Neuro-transmitters are the chemicals which transmit signals between the cells in our brains. In depression, some of the neurotransmitter systems, particularly those of Serotonin and Noradrenaline, don't seem to be working properly. We think that antidepressants work by increasing the activity of these chemicals in our brains.

What are antidepressants used for?

They are used to treat moderate to severe depressive illnesses. They are also used to help the symptoms of severe anxiety, panic attacks and obsessional problems. They may also be used to help people with chronic pain, eating disorders and post-traumatic stress disorder. Don't assume that because you have been prescribed an antidepressant that this means you are suffering from depression. If you are not clear about why you have been given them, ask your doctor.

How well do they work?

Studies have found that after 3 months of antidepressant treatment between 50% and 65% of the people who take them will be much improved. This compares with 25 - 30% of people given an inactive "dummy" pill, or placebo. It may seem surprising that people given placebo tablets improve, but this happens with all tablets that affect how we feel - the effect is similar with painkillers. Antidepressants do seem to be helpful but, like many other medicines, some of the benefit is due to the placebo effect.

Are the newer ones better than the older ones?

Yes and no. The older tablets (Tricyclics) are just as effective as the newer ones (SSRIs) but, on the whole, the newer ones seem to have fewer side-effects. A major advantage for the newer tablets is that they are not dangerous if someone takes an overdose of them.

List of Antidepressants - SSRIs, MAOIs, Tricyclics, Others

next: SNRI (Serotonin-Norepinephrine Reuptake Inhibitors)