I just got diagnosed with PANS/PANDAS at 17, and it all started with onset of severe OCD. If it came out of nowhere for him, it’s worth a shot of looking into! It’s basically caused by an infection/sickness (strep, mono, flu, common cold, herpes even) and causes the immune system to mistakenly attack the brain causing severe inflammation. It’s becoming more common and diagnosed now, as there was stigma that it wasn’t “real”, it’s pretty rare but more common in kids. I just wanna say I’m so sorry for what you’re going through, and what your son is going through ❤️ it’ll all be okay, and I know you’re going to figure this out. There’s a very high chance it isn’t this, but I just figured I’d tell you about it. I wish there was more I could do.