Does this effect last after they stop playing tetris, or just while they play? I know when I played tetris a lot, my brain seemed to be stuck on it in a way. I would close my eyes and almost see tetris shapes. I'd have dreams about it. And I would kind of see various problems through a tetris lens, so to speak.

I wonder if that phenomenon is what is going on here. Your brain uses slightly different pathways that are tetris influenced and have lower risk of jumping into the PTSD paths.

I wonder if that lasts after they stop playing and their brain reverts to non-tetris influenced ways of thinking.