Apparently, FND has neurological characteristics found nowhere else in medicine. Which ones? Excellent question. Unfortunately, instead of an answer, we've been offered a lecture about pilots, professional qualifications and AIDS denialism. Welcome aboard. Scientific evidence is apparently not included in the ticket price.

ME/CFS? Stop pacing. Long COVID? Think functional. POTS, MCAS or CCI? Perhaps FND. We examine ten controversial public statements from an FND-specialist physical therapist, the evidence behind them, and the potential consequences for patients.

Christina Applegate reveals that doctors have withdrawn her multiple sclerosis diagnosis after five years of debilitating symptoms. Her disability remains, her condition has reportedly worsened, and the search for an explanation starts again. The case raises questions about neurological misdiagnosis and the danger of replacing one incorrect diagnosis with another.

An FND-focused healthcare professional accuses Selma Blair of seeking sympathy, questions her MS history using dancing videos and declares her symptoms textbook FND. Apparently, hysteria got a rebrand, not a retirement.

A Doctor of Physical Therapy claims a 50-minute seizure can only be functional. But prolonged epileptic seizures are medically documented. This raises serious questions about professional authority, diagnostic overreach, positive signs, and the dangers of diagnosing patients on social media.

FND researchers acknowledge that weak functional signs lack specificity, neurologists disagree, and unfamiliar diseases risk being labelled functional. The diagnostic problem is hiding in plain sight.

David Healy's warning that drug toxicity can disappear behind an FND diagnosis has provoked predictable criticism. But much of the response confuses how FND is supposed to be diagnosed with how it is actually diagnosed. The literature itself shows misdiagnosis, overdiagnosis and diagnostic overshadowing occur. You can dislike Healy's language. You still have to answer his argument.

We examined repeated public claims about FND made by an allied health professional who treats the disorder for a living. Some are supported by the literature. Others go much further than the evidence allows. The recurring problem is simple: evidence seems much better at confirming FND than disproving it.

Davenport et al.’s comparison of Long COVID, ME/CFS and FND has drawn criticism, but some apparent errors expose a deeper problem: when FND can resemble almost every common neurological phenotype, definitions can determine the answer before the differential even begins.