As you report, the research of loneliness by John Cacioppo of the University of Chicago and his colleagues shows that it is a contagious disease (“Alone in the Crowd,” December 12, 2009). As soon as one person in a social network starts expressing feelings of loneliness, others within the same network start feeling the same way. The feeling spreads. The trouble is that in many species loneliness increases the likelihood of illness and reduces the lifespan. It is thus like a collective suicide. But this goes all the way to the cellular level, as well. According to Howard Bloom’s Global Brain (2000), loneliness is akin to apoptosis, a string of self-destruct routines preprogrammed into nearly every living cell. The process is initiated when the cell receives signals that it is no longer needed by the larger cell community. Such signals spread to neighboring cells performing the same function. In other words, the research results are hardly surprising.  Loneliness has been a kiss of death throughout evolution.