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Antidepressants

Antidepressants are the main treatment for moderate-severe depression. In clinical trials, 50-65 per cent of people given antidepressants show an improvement in symptoms compared to 25-30 per cent of those given a placebo. Most people experience an improvement in mood and energy levels within six weeks of starting to take antidepressants.

There are several different classes of antidepressant. The most common are:

  • Tricyclic Antidepressants (TCAs)
  • Selective Reuptake Inhibitors (SRIs)

TCAs were first developed in the 1950s as a treatment for epilepsy, but were found to produce a marked improvement in mood, and were adopted as a treatment for depression. Although it is not entirely clear how they work, TCAs are thought to increase levels of chemicals called serotonin, noradrenaline and dopamine that are thought to become depleted when you are depressed. While TCAs are effective as a treatment for depression, they can have unpleasant side effects, and are unsuitable for anyone with heart or liver disease.

SRIs were developed in response to the side effects associated with TCAs. There are three common types of SRI:

  • Selective Serotonin Reuptake Inhibitors (SSRIs) such as Prozac focus solely on raising the levels of serotonin in the brain
  • Selective Noradrenaline Reuptake Inhibitors (NARIs) such as Reboxetine focus solely on raising the levels of noradrenaline in the brain
  • Serotonin and Noradrenaline Reuptake Inhibitors (SNRIs) such as Venlafaxine raise the levels of both serotonin and noradrenaline

SRIs have no greater antidepressant effect than TCAs, but are generally better tolerated, and have fewer side effects. SRIs are also significantly less toxic in overdose than TCAs. For these reasons, they have become the most common first treatment for moderate-severe depression, with most doctors prescribing either Prozac (or its generic equivalent, fluoxetine) or Cipramil (or its generic equivalent, citalopram) in the first instance.

Several other antidepressants that do not fit into these groups are also available. Mono Amine Oxidase Inhibitors (MAOIs) have been around since the 1950s, but are seldom used today because they can have dangerous interactions with certain foods (most notably cheese). One newer MAOI - moclobemide - was developed in the 1990s to address this problem, but it is rarely used today. Other antidepressants such as flupentixol, mirtazapine and trazadone are used today, but generally only if intitial treatment with an SSRI has not succeeded.

Side Effects

As with all medicines, antidepressants can have unpleasant side effects. The most common are:

  • Headaches
  • Stomach upsets
  • Nausea
  • Dry mouth
  • Dizziness
  • Constipation
  • Sweating
  • Tiredness
  • Disrupted sleep

For most people, these side-effects are mild, and pass after a few weeks. However, for a minority they can be severe and may outweigh any beneficial effects on depression. For this reason it is important to discuss side effects with your doctor or pharmacist, as it may be possible to find another antidepressant that you find easier to tolerate.

Withdrawal symptoms

Antidepressants are not addictive - they do not cause cravings, and you do not have to take higher doses to achieve the same outcome. However, some antidepressants can have unpleasant withdrawal symptoms. Some withdrawal symptoms can appear to be a re-emergence of your depression. Others will be unlike depression. These can include:

  • Headaches
  • Dizziness
  • Muscle spasm
  • Tremor
  • Mild (but unpleasant) electric shock sensations
  • Agitation

It is not advisable to stop taking an antidepressant abruptly. In most cases, your doctor will gradually reduce the dose over 4 weeks in order to minimise the symptoms.  Most people are able to come off antidepressants with few withdrawal symptoms.  However, a small number can have more serious problems, and may need to withdraw more slowly over a period of several months.

The important thing to remember is that any withdrawal symptoms are not the re-emergence of your condition, and will diminish with time.


Do antidepressants cure depression?

Although antidepressants have an important role play in the treatment of depression, it would be wrong to regard them as a "cure" in the same way as a course of antibiotics is a cure for a bacterial infection. Depression is a complex condition that has socio-economic, physical, psychological, biochemical and even existential elements that all need to be addressed in order to achieve sustained recovery.

While antidepressants are effective in lifting the symptoms of depression, remission rates are high:

  • Half of the people who have been successfully treated for depression will experience another episode
  • Three-quarters of these will have a third episode
  • Ninety-five per cent of these will have four or more episodes

Rather than seeing antidepressants as a "cure", it is better to regard them as a source of support to allow you to address the wider causes of your depression and to develop coping strategies to help you achieve a sustainable recovery.