During puberty, young people become particularly sensitive to peer influence – more so than at any other time in life.
So, how does this affect their mental health?
A new study from Finland, released today, analyzed data from more than 600,000 young people born between 1985 and 2000 (that’s both millennials and early Gen Zs).
It found that people whose peers had been diagnosed with a mental health condition – such as anxiety or depression – were more likely to develop a mental health condition themselves.
The researchers say these findings support the idea of the “social contagion” of mental health conditions. But we must be careful: this does not mean that these conditions are “contagious” in the same way as an infectious disease.
Many other factors, including genetic predisposition, also play a role in adolescent mental health. The data also cannot tell us whether “peers” are actually friends. Let’s take a look.
Mental health conditions on the rise
Around the world, depression and anxiety are on the rise among young people. In Australia, recent data shows that anxiety rates among young people have risen from 13% to 28% over the past 15 years, while suicide attempts doubled.
Despite greater awareness and expanded mental health servicesyoung people face more serious and complex mental health challenges than ever before.
We know that both friends and family play an important role in mental health. Family factors – incl genetics – and environmental influences – such as e.g peer relationships – each uniquely shapes the progression of mental health conditions.
What the study did and what it found
The new Finnish study investigated the relationship between the mental health of young people and their peers. It aimed to find out whether having a peer with a diagnosed mental health condition, or a peer with a family history, increases the odds of a diagnosis.
The researchers did this by analyzing nationwide data in Finland, including health records and school enrollments.
The study came up with some interesting key findings:
if you had a peer diagnosed with a mental health condition or a peer with diagnoses in their family – for example, anxiety – you were more likely to be diagnosed with the same condition
The effect was stronger among peers who attended the same school, rather than living in the same area – particularly in later adolescence.
The authors conclude that the findings support the idea of ”contagion” of mental health risk in adolescence.
But there are some important caveats
It is important to note that terms such as “contagion” or “contagion” are not used in the same way as for infectious diseases. You cannot ‘catch’ a mental health condition.
Rather, these terms describe how emotions, behaviors, and social norms can spread among peers over time and affect mental health. For example, if there is increased mental health awareness and reduced stigma in a peer group, people in that group may be more comfortable seeking help (although the study did not test this).
Importantly, peer relationships and genetic risk are part of a complex mix of factors that shape adolescent mental health.
Because this study defined peers by school year or location, the findings likely reflect shared school and community influences. In other words, these “peers” were likely exposed to similar environmental conditions, ranging from school cultures and educational approaches to neighborhood characteristics such as green space.
What the study couldn’t measure
The size of this study is a key strength. However, because this is achieved using ‘registry data’ such as health records, there are some limitations:
the data can’t tell you if people actually knew each other or were friends. So the study defined “peer networks” by school (for example, people in the same class and born in the same year) or where they lived (for example, people in the same zip code who were born in the same year)
“Genetic risk” came from family diagnoses, not DNA, and there can be a number of reasons why someone with a mental health condition goes undiagnosed
the study was unable to account for all factors known to increase or decrease someone’s risk of having a mental health condition. For example, it included gender, age, and the income and education level of one’s parents. But he didn’t take other factors into account known to play a role on adolescent mental health, such as gender identity, ethnicity and what their school is like, as well as lifestyle behaviorssuch as whether they smoke, drink alcohol or exercise regularly
The study also found that if someone’s peer had a family history of a mental health condition, such as a substance use disorder, they were more likely to receive the same diagnosis. But because the data only looks at diagnosis, it can’t capture other factors that might better explain the link — such as shared factors in the families’ social environment.
Where next?
This study shows that both peer and family risk are associated with adolescent mental health, but cannot explain how these effects occur.
To understand how mental health conditions “spread” through peer networks, we still need research which disentangles the effects of peer selection (choosing similar friends) from peer influence (how friends shape each other).
But the importance of the school environment is clear. School-based mental health programs that leverage influence role of peers they are basic. In Australia, a program called Look after your partneralready promised reducing the risk of depression in adolescents through education about mental health and how to support peers.
Together, these findings point beyond individuals to the broader environments to which young people belong. Ultimately, improving adolescent mental health means investing in the people and spaces around them, such as schools and communities where peer relationships are formed.
We thank Professor Cath Chapman for her role in the development of this article.
If this article has raised issues for you or if you are concerned about someone you know, please call Lifeline on 13 11 14. Aboriginal and Torres Strait Islander people can also call 13YARN on 13 92 76.
