What do psychosis, psychedelics and sleep deprivation have in common? They make you really bad at perceiving visual illusions…and really good at hallucinating.

Driven by bewilderment, a hunch, and a sense of purpose, I set out to determine how sleep deprivation causes visual hallucinations. My quest turned up a key paper (written entirely in German), a new hypothesis and a vow to get more sleep. Below is an exposition of my journey, beginning about a decade ago.