New research suggests that both good and bad moods can be “picked up” or transferred from friends, but depression cannot.
In the study, U.K. investigators examined whether friends’ moods can spread across friendship networks and affect other individuals.
To do this, University of Warwick researchers analyzed data from the National Longitudinal Study of Adolescent to Adult Health which incorporates the moods and friendship networks of US adolescents in schools.
Investigators believe their findings imply that mood does spread over friendship networks, as do various different symptoms of depression such as helplessness and loss of interest. However, they also found that the effect from lower or worse mood friends was not strong enough to push the other friends into depression.
Using mathematical modelling they found that having more friends who suffer worse moods is associated with a higher probability of an individual experiencing low moods and a decreased probability of improving. Conversely, they found the positive moods can spread among teens who had a more positive social circle.
Public health statistics researcher Rob Eyre, a Warwick doctoral student, led the study. Investigators looked for evidence for the individual components of mood (such as appetite, tiredness, and sleep) spreading through U.S. adolescent friendship networks; they then adjusted for confounding by modelling the transition probabilities of changing mood state over time.
“Evidence suggests mood may spread from person to person via a process known as social contagion,” Eyre said.
“Previous studies have found social support and befriending to be beneficial to mood disorders in adolescents while recent experiments suggest that an individual’s emotional state can be affected by exposure to the emotional expressions of social contacts.
“Clearly, a greater understanding of how changes in the mood of adolescents are affected by the mood of their friends would be beneficial in informing interventions tackling adolescent depression.”
The World Health Organization has estimated that depression affects 350 million people across the world, impacting on individual’s abilities to work and socialize and at worse leading to suicide.
Researchers believe the findings emphasize the need to also consider those who exhibit levels of depressive symptoms — just below those needed for a diagnosis of actual depression — when designing public health interventions.
The study also helps confirm that there is more to depression than simply low mood. At the individual level, these findings imply that following the evidence-based advice for improving mood, e.g. exercise, sleeping well, and managing stress, can help a teenager’s friends as well as themselves.
But for depression, friends do not put an individual at risk of illness so a recommended course of action would be to show them support.
The study conclusions link in to current policy discussions on the importance of sub-threshold levels of depressive symptoms and could help inform interventions against depression in senior schools
Co-author Dr. Frances Griffiths of Warwick Medical School said, “The results found here can inform public health policy and the design of interventions against depression in adolescents. Sub-threshold levels of depressive symptoms in adolescents is an issue of great current concern as they have been found to be very common, to cause a reduced quality of life and to lead to greater risk of depression later on in life than having no symptoms at all.
“Understanding that these components of mood can spread socially suggests that while the primary target of social interventions should be to increase friendships because of its benefits in reducing of the risk of depression, a secondary aim could be to reduce spreading of negative mood.”
The study is published in the journal Royal Society Open Science.
Source: University of Warwick