The antidepressant Prozac and related drugs are no better than placebo in treating all but the most severely depressed patients, according to a damaging assessment of the latest generation of antidepressants.
SSRIs, or selective serotonin reuptake inhibitors, were supposed to revolutionise care of depression 鈥� by treating symptoms without the side effects of older drugs, such as tricyclics.
But despite selling in vast quantities, a new meta-analysis of these drugs, from data presented to the US Food and Drug Administration (FDA), appears to suggest that for most patients they do not work. A previous study had indicated that the benefits of antidepressants might be exaggerated.
Advertisement
UK and US researchers led by of Hull University, UK, studied all clinical trials submitted to the FDA for the licensing of the four SSRIs: fluoxetine (Prozac), venlafaxine, nefazodone, and paroxetine (Seroxat or Paxil), for which full datasets were available.
They conclude that, 鈥渃ompared with placebo, the new-generation antidepressants do not produce clinically significant improvements in depression in patients who initially have moderate or even very severe depression鈥�.
Dishing out drugs
They did detect some benefits in the most severely depressed patients. But conclude that in this group the small effect is 鈥渄ue to decreased responsiveness to placebo, rather than increased responsiveness to medication鈥�.
Given these results, they say that there is little reason to prescribe SSRI medications to any but the most severely depressed patients.
David Healy, a psychiatrist at Cardiff University, UK, specialising in the use of SSRI drugs, says the latest study confirms suspicions that the drugs鈥� effectiveness had been dramatically overstated.
鈥淢ost importantly this new study shows that the people who did respond to the drugs would have responded to placebo, anyway.
鈥淚t confirms that GPs should not be dishing these drugs out as first-line treatment for mild depression,鈥� he told New 杏吧原创. The drugs were, he notes, 鈥渞outinely being given to people who would get better without them鈥�.
Positive results
Eli Lilly, which manufactures Prozac, says that 鈥渆xtensive scientific and medical experience has demonstrated it is an effective antidepressant鈥�. It adds that: 鈥淢ore than 50 million people with depression have been treated with Prozac since its launch.鈥�
A spokesman for GlaxoSmithKline, which makes Seroxat, points out that the study only looked at a 鈥渟mall subset of the total data available鈥�.
Healy notes however, that drug companies have tended to publish studies showing positive results of the SSRIs in mildly depressed patients.
He says too that there have been concerns that SSRI drugs, particularly paroxetine, may cause dependence in some patients, and this underlines the need to avoid their unnecessary prescription.
Placebo benefit
Healy warns however, that anyone taking SSRI antidepressants should not suddenly stop taking their medication and should consult their doctor before coming off the drugs.
David Nutt, a psychopharmacologist at Bristol University, UK, points out that if SSRIs provided some sort of placebo benefit, this should not be discounted. He notes that 鈥渢he true drug effect is that of the drug added to that of placebo which is not the same as no treatment鈥�.
Earlier this month, New 杏吧原创 reported claims by US lawyers that they had obtained documents suggesting that an inappropriate analysis of clinical trial data by researchers at GlaxoSmithKline had obscured suicide risks associated with paroxetine for 15 years.
Journal reference: PLoS Medicine
Mental Health 鈥� discover the latest research in our continuously updated special report.
