The interesting thing is how any drug has such a specific "tiny people" effect, and what that says about how our brain works. The fact that many people report the same thing seems to imply there is a common cause based on how our perceptual system works - a separation of classification/identification (it's a person) from size determination. There seems to be a similar effect in very young children who think they can sit on a tiny dollhouse chair, or in a tiny toy car.

I wonder how specific this "tiny people" effect is - is it just tiny people, or also tiny animals, or maybe distorted size perception in general (with the tiny people being the most noticeable part of that)?