Root cause of Stress and Depression

All stress and depression starts with one Negative thought, which goes unchecked and becomes a reality in the mind. Repeat negative thinking makes the negativity like an unmovable mountain in the head, in the end leading to depression & other psychological/health issues.
So how to deal with it??

If you get any negative thought, first of all check its reality. Is it giving you a signal for behavioural change? then go for it. Change your course of action, till you become satisfied.If its just phoney, then change your perception and look for the positive alternative.
Practice this Mental Exercise for 1 week and see the phenomenal changes in your life!!!
Feel free to share your experiences.