I had a penpal once who had been diagnosed with mild schizophrenia. (Which I think is like being 'a little bit pregnant'). He said he imagined everything coming in over his computer was artificial, that nothing at the other end of the line was real.
I can kind of see how people could think that. If you're old enough that you didn't grow up with computers, the computers themselves seem scary smart. Even without connecting to the Internet, you can have a conversation with the computer itself, or even a smartphone these days. You can play games against the computer. If you're not totally used to computers, like we are these days, you might be confused as to what's another person and what's the computer itself.
Even in the earliest online games, you could play against the computer or against another player at some undisclosed mysterious place on earth. And there wasn't much difference! You don't SEE another person, like you would in a board game or a card game, you just see cartoons on the screen. Even if you knew the difference you might not know which it is!