Are antidepressants no better than placebo?

Millions of people taking commonly prescribed antidepressants such as Prozac (fluoxetine) and Seroxat (paroxetine) might as well be taking a placebo, according to media reports.

UK researchers found that the antidepressant drugs worked no better than a placebo for the majority of patients with mild or even severe depression.

But the manufacturers of the antidepressants warn that the study failed to take into account the positive health benefits of the drugs.

The findings come at a time when the DoH is looking to reduce the reliance on antidepressants by increasing access to psychological therapies.

The DoH will invest £170 million to train an extra 3,600 psychological therapists in England.

By 2011, all GP practices should have access to psychological therapies allowing an extra 900,000 patients with depression to be treated.

What is the research?
The reports are based on a UK study that examined 47 clinical trials on the effectiveness of fluoxetine, paroxetine, venlafaxine (Effexor) and nefazodone (Serzone).

Published and unpublished studies submitted to the US Food and Drugs Administration were obtained under the Freedom of Information laws.

This allowed the researchers to avoid bias that might come from the non-publication of disappointing findings.

Additional data was found on an online medical search engine and, for nine trials with incomplete data, pharmaceutical company websites were also used.

Meta-analysis showed that, overall, patients taking antidepressants improved control of their depression.

But no clinically significant differences were seen between antidepressants and placebo in mildly depressed patients nor in the majority of patients with severe depression.

Only in some of the most severely depressed patients did the antidepressants show any benefit over the placebo.

However, the researchers say this may be due to a decrease in response to the placebo drug rather than an increased response to the antidepressant.

What do the researchers say?
Lead researcher Professor Irving Kirsh, from the department of psychology at the University of Hull, said: 'The difference in improvement between patients taking placebos and those taking antidepressants is not very great.

'This means that depressed people can improve without chemical treatments.'

'There seems little reason to prescribe antidepressant medication to any but the most severely depressed patients, unless alternative treatments have failed to provide a benefit.'

What do other experts say?
Dr Tim Saunders, GP and mental health lead for Chester West PCT, said: 'There is no need for a knee-jerk reaction to one study on antidepressants. I would advise GPs to continue to prescribe antidepressants in line with NICE guidance.'

NICE guidelines, issued in May 2007, state that antidepressants are prescribed to people with moderate or severe depression who have already been offered computerised cognitive behavioural therapy or psychological interventions.

Dr Chris Manning, chief executive of the charity Primary Care Mental Health and Education, said: 'I am convinced that there is a population of people with depression who will continue to require antidepressants.'

But Dr Ian Walton, a GPSI in psychiatry in Sandwell, West Midlands, said antidepressants had not been as effective as hoped despite a doubling of prescriptions in 10 years.

'We are piloting alternatives to antidepressants such as psychological therapy and positive mental training at our practice,' he said. 'It is important to help patients tackle the underlying causes of their depression.'

PLoS Medicine 2008; 5: 260-8

Informing patients

  • Antidepressants may be no better than placebo for treating depression.
  • Antidepressants can improve symptoms in people with depression.
  • NICE recommends antidepressants for people with moderate to severe depression.
  • Cognitive behavioural therapy can help treat depression.

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