Friday, May 1, 2015
Low Serotonin, Depression Link a Myth?
The concept that depression is a result of low brain serotonin levels and, therefore, that selective serotonin reuptake inhibitors (SSRIs) are an effective treatment for the disorder is a myth, says a UK psychiatrist.
Moreover, David Healy, MD, professor of psychiatry, Hergest Unit, Bangor, Wales, United Kingdom, believes that SSRIs were a treatment looking for a condition and that doctors and patients were co-opted into the myth by clever marketing, resulting in better treatments being sidelined.
"This history raises a question about the weight doctors and others put on biological and epidemiological plausibility. Does a plausible (but mythical) account of biology and treatment let everyone put aside clinical trial data that show no evidence of lives saved or restored function?," Dr Healy asks.
"In other areas of life the products we use, from computers to microwaves, improve year on year, but this is not the case for medicines, where this year's treatments may achieve blockbuster sales despite being less effective and less safe than yesterday's models," he adds.
The editorial was published online April 21 in the BMJ.
Doctors, Patients Co-opted
Outlining the history of SSRIs, Dr Healy says that in the 1960s, the notion that serotonin levels are lower in persons with depression was rejected, and SSRIs were shown to be less effective than tricyclic antidepressants. The SSRIs were then marketed as tranquilizers, for which they were equally unsuccessful.
They only found a place in the market when it was suggested that depression is the "deeper illness" behind anxiety. This notion was predicated on the idea that a there is "chemical imbalance" of serotonin levels in the brain that needs to be normalized.
Dr Healy suggests that this concept initially took root in the lay public and became co-opted first by the complementary health markets and then by psychologists, among others.
In his editorial, he says: "Above all, the myth co-opted doctors and patients."
"For doctors, it provided an easy short hand for communication with patients. For patients, the idea of correcting an abnormality has a moral force that can be expected to overcome the scruples some might have had about taking a tranquilliser, especially when packaged in the appealing form that distress is not a weakness."
The result is that there are now more prescriptions for antidepressants than there are people in the Western world, Dr Healy writes.
One of the main issues with the rise of SSRIs, he says, is that "more effective and less costly" treatments have been marginalized. Furthermore, research into other, more plausible explanations for depression ― as illustrated, for example, by the antidepressant potential of ketamine ― has been stifled.