More than five years after the start of the pandemic, long Covid remains without a treatment, due to a lack of certainty about its causes. A minority of researchers, particularly in France, persist in suggesting psychological factors, angering patient associations.
"In 2026, it is unacceptable to psychologize this," says Ryan, a young man who has had long Covid for four years and who came to demonstrate on Friday in front of the Hôtel-Dieu (AP-HP), an emblematic hospital in the heart of Paris, with about ten other patients.
All are affected by this pathology which appeared with the Covid pandemic in the early 2020s and is characterized by lasting symptoms after the infection itself: fatigue, respiratory problems, muscle pain…
It's difficult to estimate how many people are affected, as definitions vary regarding the time frame after which one can be considered long Covid. However, according to estimates from the World Health Organization (WHO), 61% of Covid patients eventually developed a prolonged form of the illness.
Today, many patient associations are expressing great frustration, like the French Winslow Santé publique, which organized Friday's gathering.
They regret a lack of recognition from health institutions, as well as the lack of avenues offered by research in terms of treatments.
However, long Covid has given rise to an unprecedented amount of research in the field of so-called "post-infectious" syndromes, such as, for example, lasting disorders following Lyme disease, which are often understudied.
Several mechanisms are suspected: the persistence of the Sars-Cov-2 virus in the body, a lasting inflammation of the tissues, or a dysregulation of the immune system which would turn against itself.
But these different approaches have not led to any effective treatment.
"There are more than a dozen clinical therapeutic trials being launched around the world, but we are in total failure," lamented Mireille Laforge, a researcher at the French National Centre for Scientific Research (CNRS), this week during a press conference organized by the ANRS Emerging Infectious Diseases Institute (ANRS MIE).
According to the researcher, this failure is explained by the fact of "not aiming well": there are probably several long Covids that do not stem from a single mechanism but from various physiological processes.
– “Harm to patients” –
It is in this context that a dissenting school of thought is making its voice heard again. In an opinion piece in the newspaper Le Monde, published by the French psychiatrist Cédric Lemogne, researchers called at the end of 2025 for a focus on "a science of symptoms" instead of focusing on the identification of physiological causes.
The article sparked strong opposition from several associations – and other researchers – for whom it was essentially a matter of reviving the theory of a long Covid that was primarily psychological.
Mr. Lemogne's profile particularly irritates associations, as the psychiatrist is an integral part of a program offered at Hôtel-Dieu in response to long Covid, giving a large part to psychotherapy.
In long Covid, "the triggering factor is often physical, but not necessarily the factors that perpetuate the symptoms," Mr. Lemogne told AFP. "Among these mechanisms, some are psychological, but that's a term sometimes perceived as stigmatizing, so I could say cognitive or cerebral."
The psychiatrist points out that only psychotherapy and physical rehabilitation have had effects, albeit modest ones, to improve the lives of patients with long Covid, as illustrated by a study published in 2025 in the prestigious medical journal BMJ.
"The anti-psychiatry activism of certain associations is a missed opportunity for some patients," he argues.
But, although Mr. Lemogne denies representing a "French-centric research perspective," the psychological theory remains marginal in the scientific literature. Two reviews published in 2024 in major journals – The Lancet and Nature Medicine – mentioned only physiological explanations.
"Anxiety and psychological distress can be among the manifestations," epidemiologist Ziyad Al-Aly, author of the work published in Nature Medicine, told AFP.
"But saying that psychological disorders are a consequence of the illness is not at all the same as saying that they are the cause of the symptoms," he emphasizes.
"By mixing the two, (...) we are harming patients," he believes, also judging that the psychological hypothesis finds more "institutional" support in France than elsewhere.
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