Troubled sleep is a commonly cited consequence of adolescent drug use but it has rarely been studied as a cause. Nor have there been any studies of the extent to which sleep behavior can spread in social networks from person to person to person.
In this study, the authors map the social networks of 8,349 adolescents in order to study how sleep behavior spreads; how drug use behavior spreads; and how a friend's sleep behavior influences one's own drug use. The authors find clusters of poor sleep behavior and drug use that extend up to four degrees of separation (to one's friends' friends' friends' friends) in the social network. Prospective regression models show that being central in the network negatively influences future sleep outcomes, but not vice versa.
- If a friend sleeps ≤7 hours, it increases the likelihood a person sleeps ≤7 hours by 11 percent.
- If a friend uses marijuana, it increases the likelihood of marijuana use by 110 percent.
- Finally, the likelihood that an individual uses drugs increases by 19 percent when a friend sleeps ≤7 hours, and a mediation analysis shows that 20 percent of this effect results from the spread of sleep behavior from one person to another.
This is the first study to suggest that the spread of one behavior in social networks influences the spread of another. The results indicate that interventions should focus on healthy sleep to prevent drug use and targeting specific individuals may improve outcomes across the entire social network.