I don’t know if thinking negative can really bring on diseases such as cancer.I do believe that what we think can have an impact on our health. For myself I do know that staying in a negative mindset has brought on depression and high blood pressure. I feel if we are consumed with negativity and it is because of what someone has so to us we should forgive them. We cannot change what someone has already done to us and forgiving them is a healing process for us.
https://www.youtube.com/watch?v=KkS55Lhb0M4&rel=0