A study published in a medical journal showed that Facebook (primarily) along with other social media was responsible for the rise in teenage suicide in girls. Let that sink in.
I 100% believe that Facebook and friends are contributing to this trend but it's important to note that the linked study does not conclude that causation is present:
There is an independent association between problematic use of social media/internet and suicide attempts in young people. However, the direction of causality, if any, remains unclear. Further evaluation through longitudinal studies is needed.