Maybe I'm overthinking this but this seems kind of an odd takeaway, and bringing it front and center is a bit of slight of hand. You're refuting a claim that's

Maybe I'm overthinking this but this seems kind of an odd takeaway, and bringing it front and center is a bit of slight of hand. You're refuting a claim that's not in the headline but I guess what you think a reader's next logical step would be?: Finding: Facebook makes already depressed people more depressed -> Claim: Facebook makes undepressed people depressed. The 2nd is not claimed, the first is the result and I think facebook has a lot of do with this.