When human beings are extremely frightened, they may faint，blind or die, even there's no any physically contact. It looks psychological problem can be a physical problem temporarily or permanently.
The thing that I remind myself is that you can receive a phone call and get bad news. This will put your body into shock, a physical response such as low blood pressure or high heart rate. Not everything needs a physical impact to have a physical response.
How hard would it be to figure out if 'the phone call' could exist? The call that, upon hearing of it you drop dead or become insane. Sort of a real-world SnowCrash. After all, it's not too much of a stretch to imagine that someone already weakened would get a heart attack as a result of the effect you describe.