There really isn't enough information in that anecdotal retelling to make heads or tails of it, but from that limited information, I'd say that person probably

There really isn't enough information in that anecdotal retelling to make heads or tails of it, but from that limited information, I'd say that person probably just had a panic attack. Panic attacks cause a spike in blood pressure for most people, but for some people the opposite will sometimes happen. I used to have them from needles, and in high school I went to the ER for suspected meningitis. They had me hooked up to monitor my vitals, and when a nurse stuck me with an IV, the room suddenly filled up with panicking medical personnel because my blood pressure hit the floor. So my guess would be the subject in question took a bunch of pills, freaked out and went to the ER, and then had a panic attack because they thought they were going to die. But to answer your question, I think that if you can, by panicking, alter your blood pressure (up or down) enough to kill yourself, that just means you had some pretty messed up cardiovascular issues. You wouldn't call that "killing yourself by thought alone"; you'd call it "dying of cardiovascular disease".