Set, Setting, and Context
Set and setting are the two non-pharmacological factors that most strongly predict the outcome of a psychedelic experience. "Set" is the internal state of the person: mindset, mood, expectations, intention, mental health history. "Setting" is the external environment: physical location, other people present, music, sense of safety. Decades of research, originating with Timothy Leary in the 1960s, confirm both shape outcomes as much as the substance and dose.