It's pretty darn silly to think that airlines are somehow privy to medical records of all their passengers. How are they supposed to know which ones are suicidal? Are we going to have them start screening passengers for clearance from their doctors and shrinks?

If the passenger is not under escort, not under supervision of a 24/7 guardian appointed by the court why would anyone have knowledge of her condition?
Police also do not have access to medical records of people, much less someone just passing through on an airliner.

Nothing in any of the stories indicated she had been adjudicated as incompetent. Nothing in any of the stories indicated she was not traveling alone and unsupervised. I somehow doubt very seriously that she had a "medic alert" bracelet indicating she was suicidal, depressed or had any physical condition.