Friends spread many things between one another. Secrets, yawns, germs and even emotions, which some have suggested can be “contagious.” A happy, bubbly pal may make you feel good when times are tough, but is mood really infectious, transmitting in social networks like a disease? According to new research, it can be.
Mood disorders are a growing public health concern. With more than 350 million people worldwide and counting suffering from depression, a leading contributor to death and illness across the globe, it’s imperative that we further our understanding of such mental health problems in order to reduce the burden on the world’s population.
It may not come as a surprise that studies have found that social support and making friends can have positive effects on a person’s mental well-being. Additionally, sad news or happy stories shared by friends can alter the expression of one’s emotions, with positive or negative moods suggested to be capable of spreading like an infectious disease. But scientists don’t yet seem to have come to a consensus on whether it is healthy or low moods that can transmit in social networks, so researchers from the universities of Manchester and Warwick set out to offer some much needed clarity.
For the investigation, more than 2,000 adolescent students from US high schools were enrolled. After recording their in-school friends and depression scores, participants were followed for up to one year to examine how mood could influence that of others. After the data was gathered, the researchers modeled the spread of mood in these networks in a similar manner to how epidemiologists examine the dissemination of infectious disease.
The researchers also made sure that their methodology was not confounded by something called homophily, which is our propensity to befriend people who are similar to us. This was important, lead author Edward Hill explains in a statement, as it would have affected the results. “For example if many adolescents drink a lot of alcohol and their friends drink a lot too it may be that alcoholic drink cause [sic] depression among the young people rather than who they are friends with,” he said.
As described in Proceedings of the Royal Society B, without any prior assumptions as to which mood is more likely to be “contagious,” the researchers found that depression does not appear to spread among friends, but positive, healthy moods can. Furthermore, having enough friends with healthy moods significantly reduced depression risk, halving the chances of developing the mood disorder during a 6–12 month period. Not only that, but individuals with a sufficient number of friends with good moods were twice as likely to recover from depression during the same timeframe.
“This was a big effect that we have seen here,” lead researcher Dr Thomas House from the University of Manchester said in a statement. “It could be that having a stronger social network is an effective way to treat depression.
“More work needs to be done but it may [sic] that we could significantly reduce the burden of depression through cheap, low-risk social interventions.”