I think it is important to note that stress can cause physical sickness.  To get technical, mental stress causes oxidative stress, which can cause premature aging, reduced immune system effectiveness, and is the leading factor in most degenerative diseases.  This can be combated by a good solid nutritional program including a good balanced diet, quality nutritional supplements and plenty of extra anti-oxidants.  So diet and lifestyle choices can have a major impact on how mental stress affects your life long term.