Sleep Deprivation Influences Drug Use in Teens' Social Networks, Study Finds

ScienceDaily (2010-03-20) -- Recent studies have shown that behaviors such as happiness, obesity, smoking and altruism are "contagious" within adult social networks. In other words, your behavior not only influences your friends, but also their friends and so on. Researchers have taken this a step farther and found that the spread of one behavior in social networks influences the spread of another behavior -- adolescent drug use.
http://www.sciencedaily.com/releases/2010/03/100319202524.htm#