A friend was telling me about some happiness research that a leading sports clothing retailer had done and how useful she found their findings in planning for her up and coming Yoga Retreat. I remembered a longitudinal study done by Harvard University, This study done over 75 years with males from all walks of life show "love" to be the key to happiness, longevity and mental health and well being.
Read more about it
http://aplus.com/a/75-year-harvard-grant-study-happiness?Another interesting article on happiness talks about the chemicals that can increase or produce levels of happiness.
http://www.mindbodygreen.com/0-23924/the-brain-chemicals-that-make-you-happy-and-how-to-trigger-them.html?utm_source=mbg&utm_medium=email&utm_content=daily&utm_campaign=160227-the-brain-chemicals-that-make-you-happy-and-how-to-trigger-them