The widely held belief that depression is due to low levels ofserotonin in the brain — and that effective treatments raisethese levels — is a myth, argues a leading psychiatrist inThe BMJ this week.
David Healy, Professor of Psychiatry at the Hergest psychiatricunit in North Wales, points to a misconception that loweredserotonin levels in depression are an established fact, which hedescribes as “the marketing of a myth.”
The serotonin reuptake inhibiting (SSRI) group of drugs came onstream in the late 1980s, nearly two decades after first beingmooted, writes Healy. The delay centred on finding anindication.
After concerns emerged about tranquilliser dependence in theearly 1980s, drug companies marketed SSRIs for depression, “eventhough they were weaker than older tricyclic antidepressants, andsold the idea that depression was the deeper illness behind thesuperficial manifestations of anxiety,” he explains. The approachwas an astonishing success, “central to which was the notion thatSSRIs restored serotonin levels to normal, a notion that latertransmuted into the idea that they remedied a chemicalimbalance.”
In the 1990s, no one knew if SSRIs raised or lowered serotoninlevels, he writes; they still don’t know. There was no evidencethat treatment corrected anything, he argues.
He suggests that the myth “co-opted” many, including thecomplementary health market, psychologists, and journals. But aboveall the myth co-opted doctors and patients, he says. “For doctorsit provided an easy short hand for communication with patients. Forpatients, the idea of correcting an abnormality has a moral forcethat can be expected to overcome the scruples some might have hadabout taking a tranquilliser, especially when packaged in theappealing form that distress is not a weakness.”
Meanwhile more effective and less costly treatments weremarginalised, he says.
He stresses that serotonin “is not irrelevant” but says thishistory “raises a question about the weight doctors and others puton biological and epidemiological plausibility.” Does a plausible(but mythical) account of biology and treatment let everyone putaside clinical trial data that show no evidence of lives saved orrestored function, he asks? Do clinical trial data marketed asevidence of effectiveness make it easier to adopt a mythicalaccount of biology?
These questions are important, he says. “In other areas of lifethe products we use, from computers to microwaves, improve year onyear, but this is not the case for medicines, where this year’streatments may achieve blockbuster sales despite being lesseffective and less safe than yesterday’s models.”
“The emerging sciences of the brain offer enormous scope todeploy any amount of neurobabble. We need to understand thelanguage we use. Until then, so long, and thanks for all theserotonin,” he concludes.
Bron:PsyPost
