[open0]

> From my uninformed point of view

Due to the tone of your over-confident first post, initially I thought you were a lawyer on Facebook's payroll making a deceitful argument.

You really think Facebook's lawyers would advise disclosing a link between Facebook usage and depression found in their internal studies? Do you really think that Facebook would even ever allow for that conclusion to be reached in this particular internal study? Come on.

[oh_sigh]

Those are different questions than what OP got at with "If they did admit a link it would open Facebook to unimaginable legal liability"

Admitting to this fact could just be bad PR. Or bad for their growth and retention metrics, while not changing their legal liability.