Responses
the brain is really powerful, so it can cause the physical symptoms to show when a placebo effect takes place
for example, even when drinking a non-alcoholic cocktail, people can get drunk, turn red and pass out (happens more often than one might think, actually)
the manga just upscales these circumstances, i believe (and it shows how usobuki exploits and pushes the brain to its limits)
the one thing that that i dont get though.. is that even though its mostly a psychological thing that usobuki is doing. how come some of the deaths have this bruises, cuts and swollen body parts without anyone or the people itself touching them? (well for most of them)