Quick guide to antidepressants

Antidepressants can be very effective. They are generally non-addictive and do not lose effectiveness with prolonged use.  Three people out of four respond to antidepressants. Of those that don't, about half will respond to a different medicine.

How long does it take for antidepressants to work?

Most people with depression will respond to treatment after two weeks but in some people, it can take up to four weeks. All drugs work at the same speed.

How long will I need treatment?

Studies have shown that continuing antidepressants for at least six months after a first episode reduces the risk of further episodes. However, long-term studies of up to 10 years have shown that half to three-quarters of all those who had suffered a depressive disorder suffered a relapse. Long term treatment of up to five years may be necessary for some people.

Drug choice

Because all antidepressants are equally effective, doctors choose medication according to side-effects and how well they mix with other medicines taken. It may take one or two attempts before a suitable medication is found.

Stopping antidepressant drugs

When taken for six weeks or longer, antidepressants should not be stopped suddenly as they have the potential to cause withdrawal symptoms. These can include dizziness, anxiety and agitation, insomnia, flu-like symptoms, diarrhoea, nausea and low mood.

What are the side effects of antidepressants?

Unfortunately all the antidepressants may cause side-effects. Most of the common side effects usually wear off with time (as the body gets more used to the drug). If a particular side-effect is still troublesome after a few weeks, there is usually an alternative drug you can try.

How do antidepressants work?

Depression is thought to be caused by a reduction in the level of certain chemicals in the brain (called neurotransmitters). These affect mood by stimulating brain cells. Antidepressants increase the level of certain important neurotransmitters.

Types of antidepressants

• Tricyclics
  Tricyclics act by blocking the re-uptake of the neurotransmitters serotonin and noradrenaline, thereby increasing levels at their receptors.
• Selective serotonin re-uptake Inhibitors (SSRI's)
  SSRI's act by blocking the re-uptake of only one neurotransmitter, serotonin.
• Monoamine oxidase inhibitors (MAOI's)
  MAOI's act by blocking the breakdown of excitatory neurotransmitters, mainly serotonin and noradrenaline.

For a detailed overview of antidepressants and other medications, see Medical Methods of Treatment