Antidepressants: who needs them?

The two principal chemical compounds involved are noradrenaline and serotonin. When present in normal amounts these are thought to increase brain activity and improve mood, but they are found in reduced amounts when people are suffering from depression. This is thought to lead to the transmission of faulty messages and to be responsible for some of the symptoms of depression. Drugs that increase the levels of noradrenaline and serotonin are used to successfully treat the illness.

The main types of antidepressants
Antidepressant drugs are taken by mouth in tablet or liquid form and usually take one to three weeks to start having an effect. Side effects may happen more rapidly, but gradually lessen, so it is worth persevering with your medication. Sometimes you may be started on a low dose to get used to the side effects, but the sooner you are on an effective dose of the drug the more quickly you will start to feel better.

Most of the drugs used to treat depression belong to three main groups:

1. SSRIs (Selective serotonin reuptake inhibitors)
Group includes: Fluoxetine, paroxetine fluvoxamine, sertraline and citalopram. You may know them by the 'trade name' given by the drug company that markets the drug, for example, Prozac, Seroxat, Faverin, Lustral and Cipramil.
Used to treat: SSRIs are now the most commonly prescribed type of antidepressant drugs, and are also used to treat phobias and panic attacks. They are also extremely useful in higher doses for eating disorders such as bulimia and anorexia nervosa.
How they work: Nerve cells in the brain constantly produce, release and reabsorb the chemical serotonin. This acts on brain cells to stimulate increased brain activity and improve mood. SSRIs prevent the reabsorption of serotonin, resulting in increased levels that are free to act on the brain cells and increase stimulation.
Side effects: SSRIs cause fewer unwanted effects (side effects) than other classes of antidepressant, and are less toxic in overdose. Unwanted effects are most apparent at the beginning of a course of treatment and include nausea, diarrhoea, reduced sex drive and headache. They can also cause restlessness and anxiety.