Mental disorders can spread on youth social networks

Researchers from the University of Helsinki, the Finnish Institute of Health and Wellbeing, the University of Jyväskylä and the University of Manchester, using data from population-based registers, examined the possibility of transmission of mental disorders within social networks formed by school classes.

The study, published in JAMA Psychiatry, is the largest and most comprehensive study to date examining the spread of mental disorders on social media. It involved more than 700,000 ninth grade students from 860 Finnish schools, followed from the end of ninth grade for an average of 11 years.

Researchers have demonstrated that the number of classmates diagnosed with a mental disorder is associated with a higher risk of receiving a mental disorder diagnosis later.

"The observed association was strongest in the first year of observation. This was not explained by factors related to parents, school and area of residence. This association was strongest for mood, anxiety and eating disorders," says Associate Professor Kristian Hakulinen from the University Helsinki.

Research made possible by large Finnish registries According to Hakulinen, previous studies have found similar results: for example, American researchers observed signs of potential transmission of depressive symptoms on social networks.

However, in previous studies, social networks were usually selected by the subjects themselves, which could lead to distortions in the data. Hakulinen points out that school classrooms are social networks suitable for research because people usually cannot choose their classmates.

“Identifying social networks and monitoring adolescents was made possible by large Finnish registries. The findings greatly enhance our understanding of how mental health problems develop and how they affect others in our social networks,” he says.

Hakulinen notes, however, that the relationship observed in the study is not necessarily cause-and-effect. Moreover, the study did not look at exactly how mental disorders might be transmitted between people.

"It is possible that the threshold for seeking help for mental health issues is lowered when there are one or more people in your social network who have already sought help. In fact, this normalization of diagnosis and treatment may be considered a beneficial spread of mental disorders," says Hakulinen.

More preventative measures? Mental disorders are a significant global problem, negatively impacting people, societies and economies. According to Hakulinen, symptoms of anxiety and depression have especially increased among young people in recent years.

Previous research has shown that in about half of all cases, the onset of mental disorders in adulthood occurs before people are 18 years old. Hakulinen emphasizes the importance of preventative measures and early intervention.

“When carrying out preventive measures, it is worth considering that mental disorders can spread from one teenager to another,” says Hakulinen.

A total of 713,809 Finnish citizens born between 1985 and 1997 took part in the study. Adolescents were followed from high school until they were first diagnosed with a mental disorder, left the country, or died. Follow-up ended no later than the end of 2019, resulting in an average follow-up period of 11.4 years.