Reacción a "Mental disorders may have some ‘contagion’ effect in adolescents, Finnish study finds"

Using data from Finnish population-based registers, the authors found that students aged around 16 who had classmates with diagnoses of mental disorder received more diagnoses of mental disorder (especially) during the following year. The relationship was detected for some disorders such as mood disorders, but not for others such as substance use disorders. 

This study has several strengths. Firstly, the use of population-based registers provides a large amount of data, as they cover the whole of Finland, unlike conventional studies that rely on often small and unrepresentative samples. Moreover, to counteract the natural tendency we all have to associate with people similar to ourselves, the authors chose ‘class’ as the social network of study, and ‘class’ had not been chosen by the students but imposed by the institutions. 

There is a possibility that the results are influenced by variables not coded in the records, although this possibility is small because the authors took into account the student's specific school, as well as a relatively long list of demographic and socio-economic variables. 

It is important to note that this result does not necessarily imply a deterioration in mental health, but could even be a positive effect. For example, it could be that having classmates with diagnoses of mental disorders contributes to reducing the stigma associated with these disorders. As a result, it is possible that students who subsequently developed mental disorders felt more comfortable seeking help from the health care system.This effect would be very positive, considering that delaying help-seeking worsens the long-term prognosis.