At least a million more Britons should be put on antidepressants, the authors of the largest ever review of the drugs today conclude.
The research led by Oxford University, and published in The Lancet, examined 522 trials involving 21 types of medication over almost four decades.
All were found to be effective, yet its authors warned that just one in six patients suffering from depression are receiving treatment.
Researchers said too many GPs were “squeamish” about offering medication for depression, when they would not hesitate to ensure patients received treatment for cancer or heart disease.
The findings also constitute the first ever league tables comparing different antidepressants.
Some of the best known antidepressants in Britain – such as Prozac – and the most widely prescribed drug, citalopram – were found to be among the least effective.
Less well-known drugs, such as amitripytline and mirtazapine were found to show far greater effect in reducing symptoms of depression.
Scientists urged GPs to consider the new evidence, with a “shift” towards the drugs shown to be most effective, following the trials involving almost 120,000 patients, most of whom had moderate to severe depression.
The UK already has the fourth highest levels of antidepressant prescribing in the Western world, with a tripling in prescription levels since the millenium.
Prof John Geddes, University of Oxford head of Psychiatry said: “The access to treatment is really bad. Only about one in six people with depression receive effective treatment in high-income countries.”
“If you recognise that people are suffering from a disorder you should expect to get access to effective treatment”, he said. “Let’s make the number 6 out of 6.”
Too many GPs were reluctant to suggest drug treatment, he suggested.
“What would we think if [patients with] high blood pressure or cancer if people simply werent getting access to available treatment?” he said, suggesting that some GPs were reluctant to prescribe drugs for mental health problems.
“I think we do tend to be a bit squeamish about it, it’s more stigmatised,” he said. “Some people don’t think they are illnesses or disorders.”
Lead author Dr Andrea Cipriani said he was “very excited” about the findings, which he said provided a “final answer” to controversy over the effectiveness of the drugs.
The researcher suggested much of the opposition to prescribing of such medications came from an “ideological” standpoint rather than an assessment of the evidence.
The study analysed 522 double-blind, randomised controlled trials, including previously unpublished results, comparing 21 types of antidepressant against placebos, and against each other.
All were found to be more effective than a placebo, and researchers stressed that all might be the best drug for some patients.
But they urged GPs to consider the evidence, and shift towards the most effective drugs.
The treatments agomelatine, amitriptyline, escitalopram, mirtazapine, paroxetine, venlafaxine and vortioxetine were found to be most effective, while fluoxetine (Prozac), fluvoxamine, reboxetine and trazodone were found to make the least difference.
Drugs were deemed effective if symptoms were reduced in at least half of patients over two months.
Dr Cipriani said the “big challenge” was to increase uptake of the drugs, and to ensure those suffering from depression did not give up on treatment too soon.
“Eighty per cent of people stop anti-depressants within a month,” he said, when effects normally took at least two months, he said.
Professor Helen Stokes-Lampard, Chairman of the Royal College of GPs, said: “This research should reassure patients who are taking or are contemplating commencing antidepressants, and the doctors that prescribe them, that they are an effective treatment for depression in the short-term.”
But she said GPs should try to offer patients talking therapies, so they did not end up becoming “reliant on medication”.
Prof Carmine Pariante, Institute of Psychiatry, Psychology and Neuroscience and spokesperson for the Royal College of Psychiatrists, said: “This meta-analysis finally puts to bed the controversy on antidepressants, clearly showing that these drugs do work in lifting mood and helping most people with depression. Importantly, the paper analyses unpublished data held by pharmaceutical companies, and shows that the funding of studies by these companies does not influence the result, thus confirming that the clinical usefulness of these drugs is not affected by pharma-sponsored spin.
Prof Anthony Cleare, Professor of Psychopharmacology and Affective Disorders, King’s College London, said the study “an important piece of work.”
“It puts to bed the idea that antidepressants don’t work – all 21 antidepressants were more effective than placebo at treating depression.
“It also challenges the often-held view that all antidepressants are more or less equally effective. Several treatments do seem work better than others,” he said.
Prof David Taylor, Professor of Psychopharmacology, King’s College London, said: “This analysis of a huge number of studies of antidepressants confirms that they are much more effective than placebo – itself a powerful treatment in depression. Differences between antidepressants are smaller, although newer drugs tend to be better tolerated.
However, the most effective drug was amitriptyline – an antidepressant discovered in the 1950s. Overall this analysis of over 500 published and unpublished studies of antidepressants proves that they do indeed work.”
Dr James Warner, Reader in Psychiatry, Imperial College London, said: “This rigorous study confirms that antidepressants have an important place in the treatment of depression.
“Depression causes misery to countless thousands every year and this study adds to the existing evidence that effective treatments are available. This study also adds clarity about how effective and how well tolerated all the common antidepressants are, and should help clinicians and patients in treatment choices.”