An analysis of data from a longitudinal study of child development in Canada showed that girls who spent more hours on the internet at 13 years of age tended to have higher depressive symptoms at age 15. In the same way, girls’ internet usage at age 15 was associated with more depressive symptoms at 17. These associations were absent in boys. The study was published in Psychological Medicine. ...
So it sounds like this is based on user reported data. Aren’t boys much less likely to report depression symptoms regardless of whether they exist?
That’s a possibility they hint at at the end of the article.