When the body is part of the emotional problem

There is an emerging connection between neurodivergent emotional experience and the immune system that the clinical mainstream has barely begun to acknowledge.

Mast cell activation syndrome—MCAS—is a condition in which mast cells, part of the immune system, release excessive inflammatory mediators inappropriately. It produces a bewildering constellation of symptoms including fatigue, brain fog, headaches, gastrointestinal distress, and skin reactions. It is common, rarely diagnosed, and increasingly associated with both neurodivergent conditions and connective tissue disorders like hypermobile Ehlers-Danlos syndrome (hEDS).

A 2025 study by Weinstock and colleagues in Brain, Behavior, and Immunity—Health surveyed 553 MCAS patients and 558 controls and found dramatically elevated rates of neuropsychiatric conditions in the MCAS group (Weinstock et al., 2025). Female MCAS patients showed significantly higher rates of ADHD, OCD, bipolar disorder, PTSD, suicidality, anxiety, and depression compared to controls. The odds ratios were striking—and critically, many patients reported symptom improvement after mast-cell-directed treatment, including antihistamines.

Read that again. Psychiatric symptoms improving after antihistamine treatment.

The implications are uncomfortable for a field that has been treating these symptoms as primarily psychological. If immune dysregulation is producing or amplifying the emotional intensity, the sensory sensitivity, the fatigue, and the cognitive fog that AuDHD people experience, then treating the emotional symptoms without investigating the immune system is like mopping the floor while the tap is running. The emerging MCAS-hEDS-neurodivergence connection suggests that for some AuDHD people, what looks like emotional dysregulation may be, in part, an inflammatory process. This doesn’t mean everyone with AuDHD has MCAS. It means the question should be asked, and it almost never is.

From my forthcoming book, Understanding AuDHD (4th edition).

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Addendum:

I’m going to resist the temptation to end this chapter with advice about how to manage AuDHD emotions better, because the whole argument of the chapter has been that managing the emotions is the wrong starting point. The question is not ‘how do I regulate my feelings?’ The question is: are the circumstances producing those feelings as reasonable as my feelings say they are? And if so, which needs changing—my emotional response, or the circumstances?

The next chapter moves from the internal world to the external one: education and academic success, where the AuDHD brain meets institutional structures that were designed by people who have never, as far as I can tell, met a neurodivergent child. The emotional regulation challenges described here don’t stay at home. They walk through the school gates every morning, and what happens next is the subject of Chapter 7.

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