A recent large study by the University of Chicago, the University of California-San Diego and Harvard found that loneliness is contagious. They interviewed more than 5,000 people over the course of 10 years, tracking their friendship histories and their reports of loneliness. In the study, researchers found that lonely individuals tend to move to the fringes of society where they have fewer and fewer friends over time. However, during their relationships, they transmit their feelings of loneliness to their remaining friends. With fewer close relationships, these friends then become lonely and eventually move to the fringes of the social network, again passing their loneliness on to others and the cycle continues. The lonely people tend to treat people differently and interact negatively. Studies show loneliness can actually be harmful to both mental and physical health leading to depression, high blood pressure, increases in the stress hormone cortisol, and compromised immunity. As humans, we need quality relationships. Studies have found that we do not need many relationships but one quality relationship is very helpful.