Martha Irvine

In addition to psychological distress, some studies suggest loneliness may cause physical changes including inflammation and elevated stress hormones that may tighten blood vessels and increase blood pressure.

When was the last time you were alone, and unwired? Really, truly by yourself. Just you and your thoughts -- no cell phone, no tablet, no laptop. Many of us crave that kind of solitude, though in an increasingly wired world, it's a rare commodity.