What is the surveillance state doing to the collective mental health of the world?

The man behind the FSU shooting was worried that the government was spying on him. He was almost certainly disturbed by more than the operations of universal surveillance. That said, he is not wrong about the government spying on him, only possibly about how much the government cares.

Ernest Hemingway was paranoid that the FBI was watching him, which eventually may have lead to him committing suicide. The thing is, he WAS being watched by the FBI.

Surveillance makes people scared. It makes people paranoid. A fear that the next thing that you say might land you in trouble because everything you saying is being listened to may simply stop you from criticising the government. Alternatively, it may drive extreme beliefs that the government is trying to hurt you or worse, and your only course of action is violence.