I can't speak for 'MS' or 'everyone' with MS, but personally I DO know that stress is one of the main 'triggers' of increased MS symptoms / episodes. Tests done during these times show increased lesion activity. I am in an extreme job that adds, at times, a lot of stress. I am not in a position to completely retire, and I love what I am doing despite the stress, so I have had to actively take steps to reduce that stress. According to more recent tests, doing so has helped reduce/eliminate many symptoms and decrease lesion activity. I am no doctor, and as I said I can't speak for everyone, but I know stress reduction has and continues to prove critical for me. That's all the studies I need.