When a person is diseased and has given up on life so he/she has no chance of living because once a person starts thinking of going for a long journey he/she has only one chance in a ten for living. Medicines cannot do all the work, it needs the cooperation of our will power and then only will be able to recover fast. If we lose our hope to live then no matter how much ever medicine we take will not get cured. So,mental strength acts as a doctor to the diseases which cannot be cured by medicines.