Speaking from my experience, I do not need research to know that having a loving pet helps keep my spirits up as I spend my days alone on medical disability due to multiple sclerosis. Having that special friend who keeps me company, is there for a hug when I need one, accompanies me on walks, always has his eye on me and a tail wag simply for looking his way or saying hello makes a significant difference in the level of happiness I feel in life. Image is of me with Solomon and Josie.