Good or bad moods can be 'picked up' from friends: study

Good and bad moods can be 'picked up' from friends and spread through social networks, but the effect is not strong enough to push people into depression, a study has found.
Using mathematical modelling researchers 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.
They found the opposite applied to adolescents who had a more positive social circle.
The 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 they also found that the effect from lower or worse mood friends was not strong enough to push the other friends into depression.
"We investigated whether there is evidence for the individual components of mood - such as appetite, tiredness and sleep - spreading through US adolescent friendship networks while adjusting for confounding by modelling the transition probabilities of changing mood state over time," said Rob Eyre, from the University of Warwick in the UK.

"Evidence suggests mood may spread from person to person via a process known as social contagion," said Eyre.
"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," he said.

The World Health Organisation (WHO) has estimated that depression affects 350 million people across the world, impacting on individual's abilities to work and socialise and at worse leading to suicide.
The findings emphasise 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, eg exercise, sleeping well, and managing stress, can help a teenager's friends as well as themselves.

Whilst 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 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
"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," said Frances Griffiths, professor at Warwick Medical School.