Jordan Peterson has been diagnosed with a chronic immune system dysfunction condition after being “exposed to a particularly moldy environment,” his daughter has said.
Mikhaila Peterson said in a post on X, formerly Twitter, that her father has Chronic Inflammatory Response Syndrome (CIRS) “due to a genetic predisposition that causes the immune system to have an inability to identify and detoxify mold/bacteria in indoor air.”
Newsweek has contacted Jordan Peterson’s team, via email, for comment.
Hey guys, @jordanbpeterson is taking some time off of everything.
He was diagnosed with CIRS (chronic inflammatory response syndrome) due to a genetic predisposition that causes the immune system to have an inability to identify and detoxify mold/bacteria in indoor air (the…
— Mikhaila Peterson (@MikhailaFuller) August 13, 2025
Why It Matters
Jordan Peterson is a high-profile public intellectual with a large international audience, and his health has affected his public work in recent years, including postponed tours and canceled events.
Mikhaila Peterson’s claim also highlights a broader debate within medicine over whether CIRS is a distinct, widely accepted clinical diagnosis.
What To Know
Mikhaila Peterson wrote on X that Jordan Peterson had been diagnosed with CIRS and that the diagnosis stemmed from a genetic predisposition.
She said that Jordan Peterson had been experiencing “severely flared symptoms” after being exposed to mold while cleaning out her grandfather’s house after he passed away.
“To be crystal clear—this isn’t about akathisia or medication,” she said. “He’s not on any medication. It’s an immune system dysfunction.”
“CIRS (chronic inflammatory response syndrome) is what has been behind his multiple health issues and random severe allergies and severe food sensitivities over the years,” Mikhaila Peterson continued. “He’s really been suffering from this badly since 2017 we just didn’t know what it was called. Only eating meat helped keep the symptoms under control but it hasn’t been enough recently.”
CIRS, as described by clinicians and clinics associated with environmental and functional medicine, is a multi-system condition they link to exposure to biotoxins—commonly from water-damaged buildings—and to certain genetic HLA subtypes.
It is characterized by clusters of symptoms including fatigue, cognitive difficulties, respiratory complaints, joint pain and heightened sensitivities, according to Today’s Integrative Health, an integrative and functional medicine care platform.
But major public health agencies do not list CIRS as a standard, universally accepted diagnosis and some physicians and researchers outside environmental-medicine practices regard the syndrome as controversial or not yet established by broad clinical evidence. It is not listed as a possible health effect of mold by the Centers for Disease Control and Prevention (CDC).
Mikhaila Peterson addressed this in her post when she said: “The fact that doctors don’t generally recognize that mold exposure in indoor air is causing chronic health issues is insane.
“The fact that this is the cause behind our food sensitivities and inability to tolerate anything other than meat (for eight years now), multiple disorders and diseases in my family, and is virtually unrecognized by the medical community, is absurd. Just like the medical system didn’t recognize ketogenic diets as a treatment for mental disorders 10 years ago (and still most doctors don’t). Just like psych med withdrawal wasn’t recognized 5 years ago (and still more doctors don’t recognize it).
“This indoor air quality problem that causes Chronic Inflammatory Response Syndrome will be commonly diagnosed in the next five-10 years. I am positive about that.”
Newsweek has contacted the CDC, via email, for a response to this.
The Australian government is one of the only national governments to conduct a formal, comprehensive inquiry specifically into CIRS, carrying out an investigation into “biotoxin-related illnesses,” including CIRS.
The much-cited study in 2018 noted that there were some practitioners who argued CIRS is a legitimate condition and said: “CIRS has been defined as a syndrome, which is different from a disease. In particular, the Committee heard that a syndrome may not be supported by a consensus medical view regarding cause, testing and/or treatment and that there are no clinical guidelines pertaining to CIRS or CIRS-like symptoms.”
Jordan Peterson speaks during the Alliance for Responsible Citizenship conference at ExCel London, at the Royal Victoria Dock in east London, on February 17, 2025.
AP
What People Are Saying
Mikhaila Peterson wrote on X: “CIRS is also the explanation behind recent cancelled shows, cancelled events, sporadic appearance of being rundown and general weepiness (caused by pain). He’s pausing the podcast at the moment but we’re hopeful for a somewhat speedy recovery given we at least know what’s going on, and there is treatment, and he’s responding well although it’s pretty rough. Praise GOD that we finally know what’s been going on.”
She added: “Praying we can treat him quickly and the medical community can be more aware of CIRS and building codes can change (add ERVs to HVACs) so we can get fresh air indoors. Everyone should take this extremely seriously if they have psych, autoimmune, or neurodegenerative disorders, or have family members they live with who suffer from these disorders as mold toxicity manifests in people exposed equally, differently.”
Australia’s Department of Health told the committee investigating biotoxin-related illnesses that “CIRS is not widely recognised in the medical profession, and that there is insufficient medical evidence regarding the identification of a common cause of the symptoms that have been associated with CIRS.”
But the committee also noted that is was “concerned to hear that often desperate individuals experiencing ongoing debilitating symptoms are turned away from mainstream medical practitioners and may be exploited in ‘being sold quackery.'”
What Happens Next
Mikhaila Peterson said her father has paused his podcast and postponed European dates while he undergoes treatment.
Public-health agencies, clinicians and researchers may face renewed calls for more systematic study of health effects related to indoor mold exposure and for clearer diagnostic standards if interest in CIRS increases, though establishing consensus would require peer-reviewed clinical studies and formal guidance from major institutions.
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