Wednesday 23 May 2018

New study proves it - antidepressants work

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Stock picture

Patricia Casey

Antidepressants have attracted enormous controversy in the past 15 years or so when the newer agents - known as the specific serotonin reuptake inhibitors (SSRI's) - came on the market. They were easy to take because the side effects they caused differed significantly from those of the older antidepressants and the treatments were more easily tolerated. They were associated with huge marketing campaigns and the pharma that produced them were investing a lot of money into the development of new drugs for the treatment of a variety of psychiatric disorders.

In tandem with their increased use, they generated controversy. The most significant of these was the possibility that these drugs could trigger suicidal thoughts and behaviour in some people. This led to expensive litigation particularly in the US. But a more fundamental one was the claim that these and older antidepressants had limited effect on depressive illness and that they were little better than placebos (dummy look-alike medicines). This was the opinion of a group of psychiatrists in Britain and Ireland who belonged to the Critical Psychiatry Network (CPN). In the US the Church of Scientology provided huge financial support to similar groups.

In 2008 a meta-analysis (pooling individual studies and analysing them as a whole) examined all the data on four antidepressants submitted to the Food and Drugs Administration in the US for licensing purposes. Irving Kirsch and colleagues published this in PLos. They found that the effects of antidepressants were small and recommended that they not be prescribed in any but those who were severely depressed and not responding to other treatments like talk therapy. This did not deter psychiatrists, like myself, from still prescribing these medicines, even to those with moderately severe depression as we were seeing a speed of benefit that talking therapy could not achieve. Also, for those with recurrent depression they prevented recurrence. Nevertheless the public were mainly ambivalent about these treatments and were increasingly unlikely to adhere to them when prescribed.

Just two weeks ago a powerful new study, larger and therefore more convincing that the Kirsch study in 2008, was published in The Lancet. The lead author was Andrea Cipriani from the University of Oxford. The methods were broadly similar to the Kirsch study in that this was a meta-analysis and data on both published, but more importantly, on unpublished studies were examined. This would reduce the bias in favour of published studies that might paint a more rosy picture of benefits than was warranted. Over 500 trials on 21 antidepressants involving over 120,000 participants were included. They compared antidepressants against placebo and also against each other, an exercise that had not been done before.

The study found that one of the oldest antidepressants, amitryptiline, was the most effective followed by two newer products, mirtazepine and venlafaxine. The one the public is most familiar with, "Prozac" was among the least effective although even then it was still more effective than placebo. Compared to other drugs it had a low level of side effects. Drugs were classed as effective if they reduced the level of symptoms at the beginning of the trail by 50pc or more.

This study is important not only because it puts to bed the belief that antidepressants are not effective across a range of severity (moderate and severe) but it also points to the relative effectiveness of different products and provides a league table regarding side effects. For those who have depressive illness it will be reassuring that they are not just being given "snake oil". They can also be comforted that the benefits of individual agents can be balanced against their effects when considering which one to prescribe.

This study did not examine comparisons between medication and talking therapies and such an evaluation would be of enormous assistance in clarifying which patients are likely to benefit from one of the other treatment so that a tailored approach to treating depressive illness could be implemented. Sadness and unhappiness are universal and this study is not suggesting that these life-problems benefit from antidepressants. The challenge is distinguishing clinical depression requiring antidepressants from the inevitable distress that occurs in response to the problems that life throws up.

Suzanne Harrington: 'Prozac changed my life. It makes me feel normal'

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