As public understanding of mental illness grows, it is increasingly old news to point out that telling depression sufferers simply to "cheer up" is not an effective treatment. Beyond the basic understanding that depressive symptoms correspond to a chemical imbalance in the neurotransmitters serotonin, dopamine, and norepinephrine, modern science still has yet to provide a reliable solution to the multitude of undesirable psychological conditions grouped under the heading of “depression.” At best, pharmaceutical aids and psychological counseling can significantly alleviate depression’s effects, but the most effective treatment varies from one individual to another and is generally unpredictable (as well as time-consuming and sometimes costly). A recent study from the University of Warwick, however, suggests a more natural treatment for depression: time spent with friends.

Evidence to support this bit of advice, which isn’t as trite as it initially sounds, can be found in the Proceedings of the Royal Society B, where researchers published their peer-reviewed results under the title, “Spreading of healthy mood in adolescent social networks." Head researcher Edward M. Hill, a PhD student specializing in public health and infectious disease epidemiology, analyzed data from the 1994-1995 National Longitudinal Study of Adolescent to Adult Health, which surveyed respondents enrolled in grades 7-12 (roughly corresponding to ages 13-18). During in-home interviews, the respondents listed up to ten friends, five male and five female, and indicated the presence or absence of symptoms associated with depression. When Hill and his co-authors modeled the data 10 years later, they found that “adolescents with five or more healthy (that is, non-depressed) friends have half the probability of becoming depressed over a six-to-12-month period compared to adolescents with no healthy friends.” For the young respondents unlucky enough to already be exhibiting depressive symptoms, “adolescents with 10 healthy friends have double the probability of recovering from depressive symptoms over a six-to-12-month period compared to adolescents with three healthy friends.” In other words, healthy, happy friends were a strong influence in making a healthy, happy individual.

Fortunately, the emotional cause-and-effect seemed to be a one-way street: depressed individuals exerted no negative influence on their healthy friends. However, there is an evident paradox here, in which the individuals most likely to benefit from the cheering impact of time spent with healthy companions are also the most likely to self-segregate, thereby denying themselves an opportunity for exposure to those with more positive outlooks. The message, then, is not only that the depressed should seek happiness in the glow of others, but also that healthy friends should do their part to uplift their struggling loved ones, even if doing so simply entails spending more time with them. In any case, it’s encouraging to learn that contagion can be a force for good, as long as it’s joy that’s being spread.