Antidepressants of the Prozac type are no better than a placebo, a leading psychologist has claimed.
According to Irving Kirsch, the evidence is overwhelming that there is no link between depression and serotonin, the brain chemical that such drugs are supposed to affect.
Practising psychiatrists, however, say that it would be disastrous to use stricter criteria for the prescription of antidepressants on the basis of Professor Kirsch’s research findings. “Be very careful what you advise, because we in the surgeries will be left to pick up the pieces,” said Amjad Uppal, a consultant psychiatrist for the Gloucestershire NHS Trust.
Last year in England the NHS issued 39 million prescriptions to treat depression, more than half being for “selective serotonin reuptake inhibitor” (SSRI) drugs. Three million people took antidepressants daily. Antidepressants including Prozac and the newer generation of SSRIs, such as Seroxat, are taken to increase the level of serotonin in the brain.
Professor Kirsch argued that they worked through the placebo effect — patients expect to be made to feel better — and said that “talking treatments” such as cognitive behavioural therapy were more effective in the long term.
“Although the chemical-imbalance theory is often presented as if it were fact, it is actually a controversial hypothesis,” he said. “This is about as close as a theory gets in science to being disproven by the evidence.”
Others maintain that antidepressants do have an active biochemical influence.
“We do not fully understand how these drugs work, but there is evidence that they influence the number of neurons and the connections between neurons. You can’t draw conclusions about this because of the nature of the study,” said Hamish McAllister- Williams, a consultant psychiatrist and psychopharmacologist at Newcastle University.
He said that depression was a dangerous illness, noting that sufferers were at as high a risk of a heart attack as those who smoked 20 cigarettes a day.
Dr McAllister-Williams believed that “at least a proportion” of the effect of the drugs was “due to active ingredients, but either way they work and we really need an effective treatment”.
Dr Uppal said: “I have a very high threshold for prescribing antidepressants, but there’s no doubt in my mind they work. Research studies are artificial and do not capture the difference between effectiveness and efficacy.”
Professor Kirsch’s research, presented at The Times Cheltenham Science Festival, shows that a new drug, tianeptine, is just as effective as SSRIs in treating depression. Tianeptine, which is a serotonin reuptake enhancer, actually decreases the level of the chemical.
In comparisons of tianeptine with SSRIs and the earlier tricyclic antidepressants, the three produced virtually identical response rates: 63 per cent of patients responded to tianeptine, 62 per cent to SSRIs and 65 per cent to tricyclics. If drugs having three different effects on serotonin brought similar benefits, these could not be due to their specific chemical activity, Professor Kirsch said. “The idea that the neurotransmitter serotonin is a causal factor in depression is wrong.”
June 14th 2010
The Times Online
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