Previous research indicates that mental health conditions may be transmitted between people. For example, one study found that depressive symptoms may pass from person to person. Until now, however, there has been a lack of evidence based on the transmissibility of mental health conditions within a population-based sample.
In the current study, researchers investigated whether having classmates with mental health conditions in the ninth grade is linked to a greater risk of receiving a mental health diagnosis later in life. To do so, they analyzed population-based data from Finland including 713, 809 people born between 1985 and 1997. They cohort was followed from the year they completed ninth grade- at around 16 years old- until the end of 2019.
Altogether 47, 433 people- or 6.6%- had a mental disorder by the ninth grade. Meanwhile 167, 227 people- or 25.1% of the cohort- received a diagnosis for a mental health disorder during the follow-up. While there was no significant increase in risk linked to having one diagnosed classmate, there was a 5% increase in risk linked to having more than one diagnosed classmate.
They additionally found that the risk of diagnosis was highest during the first year of follow-up and was greatest for mood, anxiety, and eating disorders. The findings were observed after adjusting for parental, school-level, and area-level cofounders.
The researchers concluded that the findings suggest mental health disorders may be transmitted within adolescent peer networks. They noted, however, that the study did not find a causal connection, and that the study did not investigate how mental disorders might transmit between individuals.
"It may be possible, for instance, 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 for their problems. In fact, this kind of normalization of diagnosis and treatment can be considered beneficial contagion of mental disorders," said study author, Associate Professor Christian Hakulinen of the University of Helsinki, in a press release.
Sources: Science Daily, JAMA Psychiatry
