Observationally. Similar to how the data is just starting to be built on the damage smart phones and social media has on kids (something that I have been talking about for 15 years), the data will arrive. There are heaps of little pieces that point to certain outcomes (like isolation and lack of social connection for depression), but there is a meta in play.
Want to improve and will to improve are different, right? I might want to be a ninja warrior, but I don't have the will to do the training required.