MCAS and Histamine H₃ Receptors in Treatment-Resistant ADHD and Anxiety: A Patient-Led Hypothesis

This is a patient-led hypothesis paper proposing that mast cell activation syndrome (MCAS) and histamine H₃ receptor pathways may contribute to treatment-resistant attention-deficit/hyperactivity disorder (ADHD), anxiety, and post-COVID cognitive dysfunction. Drawing on personal observations and literature review, the author suggests that chronic histamine release via H₃ receptors could disrupt dopamine, norepinephrine, and acetylcholine signaling, contributing to neuroinflammation and impaired focus, mood, and cognition. This work is intended to stimulate discussion, research, and collaboration in both the clinical and scientific communities. It does not constitute clinical advice.