In the book, LSD: My Problem Child, Albert Hofman, the scientist who created LSD, wrote about how his first controlled experiment with the drug opened him up to demons:
“The dizziness and sensation of fainting became so strong at times that I could no longer hold myself erect, and had to lie down on a sofa. My surroundings had now transformed themselves in more Janefying ways. Everything in the room spun around, and the familiar objects and pieces of furniture assumed grotesque, threatening forms… Even worse than these demonic transformations of the outer world, were the alterations that I perceived in myself, in my inner being. Every exertion of my will, every attempt to put an end to the disintegration of the outer world and the dissolution of my ego, seemed to be wasted effort. A demon had invaded me, had taken possession of my body, mind, and soul. I jumped up and screamed; trying to free myself from him, but then sank down again and lay helpless on the sofa. The substance, with which I had wanted to experiment, had vanquished me. It was the demon that scornfully triumphed over my will. I was seized by the dreadful fear of going insane…” –LSD-My Problem Child, 1980, McGraw-Hill Book Company
Hofmann even acknowledges that the sense of becoming possessed by a demon after ingesting LSD is a common report among most researchers:
“Both the estrangement from the environment and the estrangement from the individual body, experienced in both of the preceding experiments described by Gelpke – as well as the feeling of AN ALIEN BEING, A DEMON, SEIZING POSSESSION OF ONESELF – are features of LSD inebriation that, in spite of all the other diversity and variability of the experience, are cited in most research reports. I have already described the possession by the LSD demon as an uncanny experience in my first planned self-experiment.”