Long-time HN lurker here, and I think it's finally time to finally create a profile and post my first comment.
I'm the CEO of an outpatient mental health organization with 50+ employees (mostly just run the tech in the background these days), I have been a professional in the field for 18 years in a wide variety of settings, and two of my four children have intermittently had symptoms that match the description of PANDAS / PANS for the past four years. Happy, gentle kids prior to it, often complemented in public for their good manners, then sudden onset for both of them after a Step-A infection, starting with neurological signs (occular shudder), then Berserker-level constant violence afterwards.
What is most maddening for parents is how powerless the whole experience leaves you feeling. I know this field, had worked with kids with these symptoms in a professional setting where I was widely viewed as the most successful clinician they had ever seen, I leveraged every asset I had to try and get my kids help (called up a family favor with the owner of a Children's hospital) and STILL the response from the hospital was to say that there was nothing wrong with my children, everything they were seeing was simply "behavioral," report me to child protection, and accuse me of Munchausen's. Close family members concluded my wife and I were child abusers when we asked them for help, and ran for the hills as soon as they got a glimpse of what was actually going on.
At the end of the day, the reality of PANS / PANDAS is even possible is not something that anyone is prepared to handle. That an innocent child could suddenly be turned into a violent weapon of mass destruction at any moment in time at the drop of a hat is a notion from a zombie apocalypse movie, not reality. Zombie apocalypse movies are actually the best possible way to imagine what it is like to live with a child with PANS / PANDAS, including the intermittent groaning biting.
To give you a clinician's perspective, when I was a young clinician working with these kids, we didn't believe it either. Neuro-autoimmune disorders were not even on the map back then, and we were always told to assume that some sort of trauma was underlying the violent behavior, because what else could possibly drive someone to do those things? Parents would tell me, "but this came on suddenly, out of nowhere, they were a happy normal kid before," and we would just assume they were lying, clueless, or some combination of the two because we could never definitely rule out that some sort of awful trauma had happened. Sure, these kids never responded well to known trauma treatments, which definitely suggested something additional was amiss, but then again there has always been a subgroup of individuals with complex trauma who do not respond well to treatment, so...
Now that I am a parent, however, and these are my own kids, I can with a high degree of confidence rule out trauma as a diagnosis in a way that I never could back then. My kids are home-schooled so it's not like we missed some sort of bullying at school, my wife and I are both professional mental health therapists so we know every parenting and behavioral conditioning trick in the book, I'm moderately wealthy and can afford to provide them with anything they need, and yet still the violent behavior continues, in complete defiance of everything I was ever taught. I sincerely wish I could apologize somehow to all those families I worked with way back when...
One of the things that makes me the most angry is the fact that the mental health system I work in is complicit in maintaining the illusion that they can help these kids. Occasionally someone will observe one of my kids acting out and will say "you should take your kids to see a therapist," as if a little routine behavioral insight could get this all fixed up in a jiffy. And if you took such a child to a therapist, they would probably be happy to attempt useless interventions on these children for years (hopefully not at my business, but perhaps even there), but the truth is that the world of mental health has nothing to offer these children. Zero, other than perhaps some palliative care for the trauma of going through and endless waking nightmare and perhaps some slightly nicer containment and quarantining facilities than you might have in your own home. I've worked in the settings where these children tend to accumulate and for the most part they simply don't...get...better. Why? Maybe because the core problem is not "behavioral," but with therapy being "so hot right now," nobody can seem to tolerate the notion that it's not a panacea for everything.
For those of you who have posted comments about your own experiences with children with PANS / PANDAS, I commend your courage and determination to continue pursuing ways to help your kids in spite of the resistance and the absolutely terrible advice the world has likely given you on how to help them. Know that you're not alone. It seems like every time I tell my story to someone, they know someone who is going through the same thing. It's possible that the frequency and prevalence of this problem is actually increasing over time, but we don't have good numbers on what exactly is happening because most of the world is still busy denying that the problem exists. I am consequently glad to see this issue getting more mainstream traction, both in the Economist and on HackerNews.
Side-note: like with most things involving the brain, I think we are unfortunately still a long way from understanding how PANS / PANDAS actually works. We have some theories, but those theories tend to not hold up well in studies (which is why PANDAS was renamed PANS to broaden the range of possible etiologies) but likely the syndrome is complex and multidimensional, with a wide variety of pathways leading to a similar endpoint (including pathways that don't even involve the immune system), sort of like Autism. So don't assume that there is a simple answer either. There are lots of stories about things like antibiotics or IVIG helping, but they don't work for everyone and each case is likely to require a slightly different approach, so the more important thing is to never give up and commit yourself to a systematic process of trial and error until you find something that works for your kids and your family. If you can, get some medical-grade genetic testing done, teach yourself some rudimentary bioinformatics, then put your tech skills to good use by mining that CRAM file for gold. That process led to tremendously helpful insights and intervention strategies for my family that would never have been uncovered otherwise.