Depression: A study into the causes of the disease sparks controversy – 08/11/2022 at 09:30

In their work, psychiatrists Joanna Moncrieff and Mark Horowitz question the use of antidepressants to treat depression that is not linked to a chemical imbalance.


(AFP / DAMIEN MEYER)

The interest of

Antidepressants would be questioned

because depression is not related to a chemical imbalance. The thesis, recently defended by a British psychiatrist, is widely disputed, but this controversy has the benefit of illustrating the difficulties in understanding this disease.

“Our study (…) challenges the basic idea behind the use of antidepressants,” affirmed psychiatrists Joanna Moncrieff and Mark Horowitz on The Conversation page in late July, introducing a paper published in the journal Molecular Psychiatry. This study challenges the serotonin hypothesis. This suggests that depression is linked to a deficiency in this molecule, which is involved in the transmission of emotions in the brain.

The work, which is based on a compilation of previous publications and is therefore more a priori sound than an isolated study, concludes

No link has been established between a lack of serotonin and the presence of depression in a person

. For its authors, it is a profound challenge to a hypothesis that has served as the framework for numerous studies for decades. In fact, the majority of current antidepressants are designed to affect serotonin levels.

A challenging study

But many critics were quick to target this study, and even more so the presentation by Joanna Moncrieff, a well-known psychiatrist

his skepticism about biological explanations for depression

, as well as his radical speech against the pharmaceutical industry. “Overall I agree with the authors’ conclusions, but I wouldn’t have such rigid certainties,” British psychiatrist Phil Cowen commented to the Science Media Center.

Criticisms of Phil Cowen and other colleagues are of various kinds. Some question the study’s methodology, particularly the fact that serotonin is not measured directly, but an indirect trace of it;

others accept his conclusions but reject their novelty

. “No mental health specialist would currently support the idea that a pathology as complex as depression is explained by a deficit in a single neurotransmitter,” notes Phil Cowen.

The argument does not apply to Joanna Moncrieff, who argues that the serotonin hypothesis, even in a reduced version, still holds an important place in psychiatric discourse. “And specially,

even as eminent psychiatrists begin to question the connections between depression and deficit

Nobody warned the general public about serotonin,” the author writes ironically on her blog, which seems to be breaking with “dominant psychiatry”.

An argument against current antidepressants

Indeed, the links between depression and serotonin are well entrenched in popular imagery. In 2019, the French author Michel Houellebecq titled a novel “Sérotonine” whose main character is depressed. But it’s not challenging the serotonin hypothesis that draws the most criticism. That is

the fact that Joanna Moncrieff argues against topical antidepressants

exceeding the conclusions of his own study.

This “is serious work, which is part of the continuation of other work and which counts in the expert discussion on the mechanisms of depression,” admits Swiss psychiatrist Michel Hofmann to AFP. ”

But I don’t think this is an article that should have any short-term impact on antidepressant prescriptions.

“, he warns. Because for Johanna Moncrieff – who has certainly warned against abruptly stopping an antidepressant at any cost – it is imperative to question the usefulness of treatments developed on the basis of a questioned hypothesis.

“We are left with hypotheses

However, many psychiatrists, including Johanna Hofmann, point out that the effectiveness of these treatments, regardless of the cause, has been scientifically studied. ”

The mechanisms of the drugs used in the treatment of depression are generally diverse

and finally, in most cases we don’t know exactly what makes a treatment effective,” he explains.

Ultimately, debates about the role of serotonin only illustrate how

It is difficult to understand the biological and social mechanisms of a disease

as complex as depression, forcing researchers to rely on models that are inherently incomplete. “We stick to hypotheses and continue to search and test models against each other,” concludes Johanna Hofmann.

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