My favorite related story is that Frankie Muniz suffers from long-term memory loss, so he doesn’t remember doing the show (specific moments become near impossible to remember if not recalled periodically). Bryan Cranston would call him up every couple of weeks and remind him of things they did during filming so Frankie wouldn’t lose the memories.

Amazing.

EDIT: I just read a clarification Muniz made in 2022. It isn’t a disorder (though he’s had nine concussions), his memory just sucks. The rest of the story still applies.