Serotonin is a molecule produced by the brain to transmit information in the nervous system. Researchers have long held responsible for regulating moods, and therefore depression.But a meta-analysis of 17 studies published in the journal Molecular Psychology this Wednesday, July 20 comes to question this theory. (source 1)
These researchers from University College London have chosen to identify all relevant studies on serotonin and depression. They thus analyzed the cases of several tens of thousands of participants, with or without mental disorder. By comparing their serotonin levels, the scientists did not no major difference noted.
In fact, the team asserts that there would be no no evidence that low serotonin causes depression.
The effectiveness of antidepressants due to the placebo effect
This discovery is important because it calls into question the relevance of certain treatments for depression. SSRIs designate a class of drugs that directly targets serotonin transporters. They are by far the most prescribed antidepressants.
According to the study, their usefulness would not be proven. In reality, we would think they are effective “through an amplified placebo effect or through their ability to restrain or dampen emotions in general”.
“Many people take antidepressants because they have been led to believe that their depression has a biochemical cause, but this new research suggests that this belief is not based on evidence”, details Joanna Moncrieff, the lead author of the study, in a press release. (source 2)
“It is high time to inform the public that this belief is not based on scientific bases”adds the professor.
This analysis caused a lot of reaction from the scientific community. Some researchers pointed out in particular that the study was able to hasty and premature conclusions.
“Antidepressants are an effective treatment (…), which can also be prescribed for a whole range of physical and mental health problems”, a spokesperson for the Royal College of Psychiatrists told the Science Media Centre. (source 3)
“The effectiveness of antidepressants varies in different people, and the reasons for this are complex. We are not recommending that anyone stop taking their antidepressants based on this study, and we encourage anyone with concerns about their treatment to contact his doctor.”