• If we were to tell you to deliberately spend ten minutes every day envisaging yourself being very ill, you'd quite rightly refuse to do it. Most people know that's a bad idea - yet those same people may spend time every day worrying about their health.

    Peter A. Cohen: If we were to tell you to deliberately spend ten minutes every day envisaging yourself being very ill, you'd quite rightly refuse to do it. Most people know that's a bad idea - yet those same people may spend time every day worrying about their health.