Not only is loneliness an unpleasant condition, it can harm the body's immune system.

NEW ORLEANS –  Feeling lonely? New research suggests you might want to reach out. Not only is loneliness an unpleasant condition, it can harm the body's immune system.The new study, presented Jan. 19 here at the annual meeting of the Society for Personality and Social Psychology, reveals that people who are lonely experience more reactivation of latent viruses in their systems than the well-connected.Lonely people also are more likely than others to produce inflammatory compounds in response to stress, a factor implicated in heart disease and other chronic disorders.Read more: 
http://www.foxnews.com/health/2013/01/21/loneliness-is-bad-for-your-health-study-suggests/