A new study looked at stressed Europeans. Those who believed their stress affected their health were 2x more likely to have a heart attack! All of the people in the study were stressed. If your mind had no impact on your health then there would be association between negative events and feeling stress impacts one’s life.
Remember, this study didn’t compare stressed to low-stress/no-stress people. My guess is that a study looking at lower-stress people would look like this:
No/low-stress informed <now/low-stress ignorance < high-stress ignorance < high-stress informed