A new large-scale study suggests that mental illness might be “transmissible” among adolescents. The research, which analyzed data from over 700,000 ninth graders in Finland, found that teens with classmates who have a mental disorder face a slightly higher risk of developing a psychiatric condition themselves later in life. While this doesn’t necessarily prove causation, the findings highlight the powerful role peer networks play in mental health.
The study found that having a classmate with a mental illness was associated with a 3% higher risk of developing a mental disorder, with the highest risk (13%) occurring in the first year of follow-up. Mood, anxiety, and eating disorders showed the strongest links. Researchers also observed a dose-response effect: the more classmates diagnosed with a mental illness, the higher the risk.
Experts suggest that this phenomenon could be explained by increased awareness, emotional contagion, and normalization of mental health struggles. When students see peers dealing with mental illness, they may be more likely to recognize their own symptoms and seek help. Conversely, long-term exposure to peers with depression or anxiety could contribute to the development of similar symptoms.
While these findings may sound concerning, they also point toward potential positive interventions. The normalization of mental health discussions and early treatment could encourage more young people to seek help. Peer support programs, which have been effective in adults, might be valuable for teens as well.
The takeaway? Mental health is not just an individual concern—it’s deeply intertwined with our social environment. Supporting each other and fostering awareness can make a big difference in how young people navigate mental health challenges.
