Rick Strassman said this quote

Psychedelics show you what’s in and on your mind, those subconscious thoughts and feelings that are are hidden, covered up, forgotten, out of sight, maybe even completely unexpected, but nevertheless imminently present. Depending upon set and setting, the same drug, at the same dose, can cause vastly different responses in the same person. One day, very little happens; another day, you soar, full of ecstatic and insightful discoveries; the next, you struggle through a terrifying nightmare. The generic nature of psychedelic, a term wide open to interpretation, suits these effects.

~ Rick Strassman