Yes, I have seen several, including one that had to be forcibly sedated in the dirt. I have also seen many drunks fighting others and police.

Over 15 years at burning man, I have seen many people injured and maimed doing stupid things while high.

That said, the type of intentional self harm described above is basically unheard of. Mostly dumb accidents and some suicides.

To the extent there is any unique risk, it is more about long term psychiatric issues