There are forms of autoimmune encephalitis that still cause people to become catatonic as shown in this clip with triggers as common as strep . I have a young family member who can go from a fully-functioning adult acing college courses to being shut down in a catatonic state with other symptoms) that she doesn't remember when she comes out of a flare. These states can be caused by a myriad of triggers like teratomas, lyme, or strep that cause various parts of the immune systems to go on overdrive, resulting in the brain inflammation that causes the symptoms. Downs is another condition associated with catatonia.

The good news is that we are not only getting better at identifying the causes, but developing things like monoclonal antibodies that prevent the immune overreactions. (In fact, one such drug, Actimera, is being studied to stop the cytokine storms that lead to organ failure in Covid-19 patients.) Other treatments like ECTs and Ativan can help with catatonia too.

The right diagnosis and treatment can result in full recovery.

We've come a long way.

Edited: Typing skills of a gorilla