Psychedelics can alter a person’s core metaphysical beliefs for as long as six months after use, study suggests

Findings from the journal Scientific Reports suggest that psychedelic drugs can alter a person’s core beliefs about the nature of reality, consciousness, and free will. After taking psychedelics, participants’ views tended to sway from physicalism to supernatural beliefs, and these changes lasted up to six months. The researchers say the findings raise ethical considerations.

Metaphysical beliefs are ideas about the fundamental nature of reality. For example, physicalism maintains that reality is entirely physical, and idealism maintains that reality is a construct of the mind. Given that psychedelics can induce transformative experiences and spiritual encounters, a team of researchers wondered whether these drugs might have the capacity to alter core metaphysical beliefs.

Study authors Christopher Timmermann and his team opted to systematically examine people’s metaphysical beliefs before and after psychedelic use and to further examine how these changes might impact their mental health. The researchers recruited 866 participants who indicated that they were about to attend a ceremony where they would be using psychedelics (e.g., psilocybin, ayahuasca, DMT). Subjects were from a wide range of countries — 44% were American, and 20% were from the U.K.

The participants completed a survey before attending the ceremony, four weeks later, and six months later. The survey included measures of metaphysical beliefs (physicalism/materialism, idealism, and dualism), free will, and determinism.

According to the findings, the participants’ beliefs veered away from physicalism after the ceremony, and this shift was significant at both the four-week and six-month follow-ups. The deviation from physicalism was strongest among respondents who were first-time users of psychedelics. The survey also revealed increases in fatalistic determinism — the belief in fate and a pre-determined future. These increases were present at the four-week mark but were only maintained at the six-month mark among those who were new to psychedelics.

Next, to better examine how participants’ views may have changed, the researchers labeled the groups based on their beliefs at baseline. They identified four groups — dualists, idealists, materialists, or none/mixed. More often than not, participants labeled as ‘hard materialists’ switched from this category to either ‘hard-dualism’ or ‘none/mixed’ after using psychedelics. At both four weeks and six months, transitioning away from hard materialism was associated with better well-being.

The researchers validated these findings with a controlled experimental trial — people who were given psilocybin therapy saw their beliefs shift away from hard materialism after the trial while people who received the anti-depressant escitalopram did not. Notably, this shift away from hard materialism was only found among patients who showed at least a 50% improvement in depression scores with psilocybin, suggesting a link between belief changes and positive mental health.

Interestingly, the extent that participants felt ‘emotional synchrony’ with other attendees predicted future changes in metaphysical beliefs, suggesting that group settings can magnify belief-change during psychedelic ceremonies. The authors say such findings call to mind historical cases of mind control assisted by psychedelics.

“Important ethical considerations are raised by the prospect of pharmacologically catalysed changes in core beliefs occurring without prior informed consent,” Timmerman and his colleagues say. “In light of these findings, future studies and services that offer psychedelic experiences may be ethically obliged to include reference to the possibility of belief change as part of informed consent procedures.”

Overall, the study authors say their findings point to “the potential of psychedelics to alter some of the most deep-seated and influential human beliefs” and “have profound scientific, societal, political and philosophical implications.”

The study, “Psychedelics alter metaphysical beliefs”, was authored by Christopher Timmermann, Hannes Kettner, Chris Letheby, Leor Roseman, Fernando E. Rosas, and Robin L. Carhart‑Harris.

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