A good mood is infectious among teens, but depression is not, a new study suggests.
A lot of happy friends
Researchers looked at more than 2,000 American high school students to see how they influenced each other's moods. They found that a positive mood seems to spread through groups of teens, but having depressed friends doesn't increase a teen's risk of depression.
In fact, having plenty of friends in a good mood can halve the chances that a teen will develop depression over six to 12 months. Having a lot of happy friends can also double the likelihood of recovering from depression over the same time period, the researchers found.
However, the study could only show an association between happy friends and a lower risk of depression or a faster recovery from depression. It cannot prove a cause-and-effect relationship between these factors.
Read: Teen girls may face greater depression risk
The study was published in the journal Proceedings of the Royal Society B.
A strong social network
"We know social factors, for example living alone or having experienced abuse in childhood, influences whether someone becomes depressed. We also know that social support is important for recovery from depression, for example having people to talk to," study author Thomas House, a senior lecturer in applied mathematics at the University of Manchester in the UK, said in a university news release.
"Our study is slightly different as it looks at the effect of being friends with people on whether you are likely to develop or recover from being depressed," he added.
Read: The depressed child
These findings suggest that promoting friendships, through such activities as social clubs, might help guard against depression, House noted.
"This was a big effect that we have seen here. 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 that we could significantly reduce the burden of depression through cheap, low-risk social interventions," House concluded.
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Image: Group of happy teens from Shutterstock