Do Psychedelics Change Beliefs?

This theory-building article (2021) examines psychedelics facilitate lasting changes in people’s beliefs and calls for better-controlled trials that assess baseline beliefs and expectations before randomizing individuals to psychedelic interventions to assay the causal role of mystical experiences in the apparent long-term effects of psychedelics.

Abstract

Introduction: Renewed interest in psychedelics has reignited the debate about whether and how they change human beliefs. In both the clinical and social-cognitive domains, psychedelic consumption may be accompanied by profound, and sometimes lasting, belief changes.

Methods: We review these changes and their possible underlying mechanisms. Rather than inducing de novo beliefs, we argue psychedelics may instead change the impact of affect and of others’ suggestions on how beliefs are imputed.

Results: Critically, we find that baseline beliefs (in the possible effects of psychedelics, for example) might color the acute effects of psychedelics as well as longer term changes.

Discussion: If we are to harness the apparent potential of psychedelics in the clinic and for human flourishing more generally, these possibilities must be addressed empirically.”

Authors: Hugh McGovern, Pantelis Leptourgos, Brendan Hutchinson & Philip R. Corlett

Summary

Renewed interest in psychedelics has reignited the debate about whether and how they change human beliefs. We review the possible underlying mechanisms of psychedelic-induced belief changes and argue that baseline beliefs might color the acute effects of psychedelics as well as longer term changes.

In 2016, psychedelic science saw a significant revival with studies administering psilocybin and LSD to healthy volunteers during functional magnetic resonance imaging. These studies promise insights into the mechanisms of consciousness and may help people with affective and addictive disorders. Psychedelics have been used for much of human history, including in Californian rock art. The CIA funded research into the use of psychedelics for mind-control and brainwashing, but the studies were poorly controlled and the drug became popular amongst the counterculture.

Many years later, it remains unclear if psychedelics can change human beliefs. The idea that psychedelics change beliefs originates from benefits observed in psychedelic-assisted therapy for treatment of complex psychiatric disorders. People who have consumed psychedelics often report transformative experiences, including increases in altruism, prosociality, connectedness, concern for nature, and decreased pessimistic outlook. These effects seem to be over and above the clinical benefits of psychedelic therapy.

Here, we aim to unpack extant findings on the changes brought about by psychedelic consumption. We urge caution, as these effects may have multiple, often indirect, mechanisms. There is probably no agreed upon definition of belief, but we can consider competing definitions and assess if beliefs change with acute psychedelic administration or in the aftermath of psychedelic exposure. Contemporary philosophers often characterize belief as a propositional attitude. However, some speculate that propositional attitudes are not unique to humans, and that believing can be a function of the strength of association between mental features that represent causes and similar features that represent effects.

Associative learning theory, connectionist networks, and more recently deep learning, have been found to explain how humans learn to make better predictions. The structure of propositional attitudes may not actually differ from simpler associative learning, and a third account of beliefs is derived from an account of the brain as an inference engine, which uses the expectation-maximization algorithm to sweep from prior beliefs to posterior beliefs. Psychedelics alter inference without much impinging upon longer-term learning, but some argue that they induce hallucinations by increasing the weighting of priors.

Whether psychedelics change beliefs critically hinges on which definition of belief is ultimately evoked. We examine the evidence of belief change under each definition, and argue that baseline beliefs are critically important. In reading, contextual effects (spatial priors) are induced by the semantic context, and these priors are implemented as feedback signals from high-level to low-level areas. Temporal priors are implemented by the dynamics of local E-I networks.

The brain generates prior expectations (priors) regarding future exteroceptive and interoceptive signals, and uses these priors to make inferences about the world’s (or brain’s or body’s) new state. Psychedelics may enhance or suppress priors, depending on the context.

Spatial priors are causal links between variables at different hierarchical levels, mediated by long-range feedback connections, and speak to the notion of cognitive penetrability. Temporal priors are based on the temporal statistics of each variable, and are less likely to rely on long-range feedback connections than spatial priors. Consequently, a strong (or weak) prior theory of psychedelics does not necessarily imply that spatial and temporal priors are equally affected. The acute and longer-term effects of psychedelics appear to be compatible with the strong-prior theory. This theory is also supported by the finding that psychedelics do not alter strong pre-existing beliefs and, if anything, further strengthen them. Several studies suggest that psychedelic usage is linked to a more positive outlook, more liberal attitudes, and self-reported positive attitudes.

Psychedelics have been shown to increase pro-environmental stances and to change belief structures, although this is not universally true.

Propositional beliefs are largely tied to language, and are used in social interactions to identify individuals as potential friends or foes. If people are shown to change their beliefs based on experimenter suggestion, then parsing whether reported changes occur due exclusively to psychedelic consumption is paramount.

Red will continue to evoke increased skin conductance, whereas blue will not. This is similar to the effects of experimenter suggestion and social norms on shaping reported outcomes in psychedelic research. Researchers found that participants’ belief-updating under social pressure increased only for beliefs that were less extreme and already in range of the norm. More extreme beliefs did not change under LSD or placebo. Psychedelics may perturb our assessment of how reliable others are, and we may defer to others more in shaping our beliefs after psychedelics, rather than psychedelics changing our beliefs wholesale.

When we draw conclusions about the mystical, spiritual, or political revelatory effects of psychedelics, we should be mindful of baseline beliefs. The themes and expectations that are primed before and during a psychedelic experience often manifest in the recipient’s experiences.

Psychedelics may not even be necessary to induce their effects, as the placebo response is so strong, and anthropological studies can also alter beliefs without the use of drugs.

Studies of psychedelics as therapeutics report correlations between the profundity of the psychedelic experience and outcome measures up to one-year post-exposure.

The persisting effects questionnaire (PEQ) measures changes in attitudes, mood, behavior, relationships, and spirituality that the user attributes to the subjective experience itself. The PEQ predicts positive outcomes including reduced anxiety and depression, and increased self-efficacy in alcohol abstinence. Changes in personality are more varied and depend on the psychedelic, with greater reductions in neuroticism and extraversion predicted by higher scores on the MEQ, and greater positive changes in attitude, behavior, and life satisfaction predicted by greater intensity of the psychedelic experience. One possibility for delineating the causal role of mystical and connectedness experiences for the clinical response is to administer the psychedelic whilst participants are sedated.

Acute intoxication with psychedelics can induce simple and complex visual hallucinations, possibly due to their excitation of 5-HT2A receptors on pyramidal neurons and consequent glutamate release, resulting in altered prefrontal cortex activity. The longer-term effects of hallucinations and mystical psychedelic experiences on beliefs remain unclear. A persistent hallucinatory persistent perceptual disorder (HPPD) occurs, in which people experience simple, often geometric, visual hallucinations, sometimes with accompanying distress. These hallucinations do not alter propositional beliefs, but instead reflect associative learning of new or differently weighted prior beliefs.

LSD has a norm-conforming impact on the 5HT2a receptor in the medial prefrontal cortex, which may underwrite the retention and strengthening of beliefs in the face of contradictory evidence in service of delusion maintenance. Future studies could assess the impact of psychedelics on social learning strategies more directly, and resolve the tension between social and non-social processes, and determine if psychedelics change propositional beliefs directly or through associations, inference, and the dissolution of the usual boundary between us and others.

Psychedelic experiences may alleviate depression, anxiety, and aid smoking cessation, in a manner that correlates with the intensity of acute mystical experiences at the time of drug exposure. The combined effects of self-dissolution and enhanced feelings of connectedness may underlie increases in positive mood and observed increases in openness. Anesthetics may produce mystical experiences, but we should pay close attention to the experiences people report upon emergence from the anesthesia. If connectedness experiences increase under acute psychedelics, we might expect psychedelics to change participants’ beliefs about pan-psychism. Since the 1990s, environmental beliefs have been more associated with the political left. However, the relationship is not so straightforward.

16 people who are interested in new-age ideas, including yoga, may end up espousing increasingly right-wing ideas. This suggests that psychedelic use may not lead to enlightenment, good outcomes, or more left-wing, collectivist ideals. We have explored whether and how psychedelics facilitate lasting belief change. We suggest better controlled trials, a broad range of psychoactive control interventions, and parametric manipulations of psychedelic settings, to assay the causal role of mystical experiences in the apparent long-term effects of psychedelics. We think that formal mathematical models of beliefs, which span computational, algorithmic, and implementational levels of analysis, may be enlightening.

17 psychedelic infusions may address many of the issues raised presently, including whether brains deal in probabilistic distributions, binary variables, or both. Psychedelic drugs may be used to treat a wide range of disorders, including depression, anxiety, and schizophrenia. Microdosing psychedelics may be used as a cognitive and emotional enhancer.

LSD acutely impairs working memory, executive functions, and cognitive flexibility, but not risk-based decision-making. 424 425 426 427 428 429 10 Robinson, D. W., Brown, K., McMenemy, M., Dennany, L., Baker, M. J., Allan, P., 430 431 Researchers found datura quids at Pinwheel Cave, California, which provide unambiguous confirmation of the ingestion of hallucinogens at a rock art site. These quids may be related to the psychedelic renaissance, which is a resurgence of interest in psychedelic drugs.

Psilocybin with psychological support for treatment-resistant depression: an open-label feasibility study. Psilocybin with psychological support for treatment-resistant depression: a six-month follow-up. Psilocybin produces substantial and sustained decreases in depression and anxiety in 470 patients with life-threatening cancer: A randomized double-blind trial.

A single high dose of psilocybin alters emotions and brain function up to one month after the dose, and produces enduring positive changes in psychological functioning and in trait measures of prosocial attitudes and behaviors. Hutson, P. R., Lyons, T., Carhart-Harris, R. L., & Jesse, R. (2018) found that high dose psilocybin was associated with positive subjective effects in 506 healthy volunteers.

Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance. Watts, R., Day, C., Krzanowski, J., Nutt, D., & Carhart-Harris, R. (2017). LSD-induced entropic brain activity predicts subsequent personality change, psilocybin-induced mystical experiences lead to increases in the personality domain of openness, and ayahuasca-induced psychedelic experiences modify personality structure.

Several studies have been conducted on the effects of psilocybin on empathy and moral decision-making, and on the forecasting of future life events. These studies have been published in the journals International Journal of Neuropsychopharmacology and Frontiers in Psychology.

Aguilera, M., Boisseau, R. P., Vogel, D., Dussutour, A., Smith-Ferguson, J., & Beekman, M. (2020). Why the content of animal thought cannot be propositional. Associative learning is a process in which people make associations between items. The propositional approach to associative learning is an alternative to association formation models, and it is based on statistical learning mechanisms.

The prediction error theory in associative learning is supported by evidence from studies in primates, rodents, and birds, and is based on the observation that the cost of obtaining rewards enhances the reward prediction error signal in midbrain dopamine neurons.

Dopaminergic computations underlie causal structure learning, but not surprise, and the link to paranoia. A Bayesian framework for understanding models of psychosis is presented, including predictions error, ketamine and psychosis, and a unifying theory of psychedelic drug effects is proposed, including strengthened beliefs under psychedelics (SEBUS).

In this text, Friston (2002) discusses functional integration and inference in the brain, Körding KP discusses free-energy and the brain, Clark (2013) discusses the predictive mind, Powers III discusses hallucinations, and Corlett et al. discuss hallucinations and strong priors.

A hierarchy of time-scales and the brain, expectation in perceptual decision making, neural and computational mechanisms, Friston K. (2008), and Felleman D. J., & Van Essen D. C. (1991). Bastos, A. M., Usrey, W. M., Adams, R. A., Mangun, G. R., Fries, P., & Friston, K. J. (2012), Vetter, P., & Newen, A. (2014), Macpherson, F. (2017), and Gold, J. I. (2017) reviewed the relationship between cognitive penetration and predictive coding.

Fischer, J., Whitney, D., Liberman, A., Fischer, J., Whitney, D., St John-Saaltink, E., Kok, P., Lau, H. C., & de Lange, F. P. (2014). Serial dependence in visual perception. Psychedelics and the essential importance of context, is a paper by Carhart-Harris, Roseman, L., Haijen, E., Erritzoe, D., Watts, R., Branchi, I., & Kaelen, M. It discusses the effects of the Amazonian psychoactive beverage Ayahuasca on binocular rivalry.

Ayahuasca, psilocybin, and white can alter binocular rivalry with dichoptic stimulus alternation, and psilocybin links binocular rivalry switch rate to attention and subjective arousal levels in humans. LSD increases suggestibility in healthy volunteers, possibly through stimulation of serotonin receptors. Carhart-Harris, Kaelen, M., Whalley, M. G., Bolstridge, M., Feilding, A., & Nutt, D. J. have also reported that LSD enhances suggestibility.

Ketamine as a possible moderator of hypnotizability: A feasibility study. Olson, J. A., Suissa-Rocheleau, L., Lifshitz, M., Raz, A., Veissière, S. P., & Dos Santos, R. G., and Hallak, J. E. C. (2010). Psilocybin-occasioned mystical-type experience in combination with meditation and other spiritual practices produces enduring positive changes in psychological functioning and in trait measures of prosocial attitudes and behaviors, according to a study by Harris, Richards, Johnson, Griffiths, Richards, W. A., McCann, U., and Jesse.

Psilocybin occasioned mystical-type experiences: immediate and persisting dose related effects. Hallucinogen persisting perception disorder: etiology, clinical features, and therapeutic perspectives. Indoleamine hallucinogens induce psychedelic effects that correlate with serotonin 2A receptor occupancy and plasma psilocin levels.

Pavlovian conditioning induced hallucinations result from overweighting of perceptual priors, a study by Powers, Mathys, & Corlett (2017) found. A drug discrimination analysis of LSD was performed by Colpaert, Niemegeers, & Janssen (1982), and by Sershen, Hashim, & Lajtha (2000). There is evidence that the medial prefrontal cortex is involved in recognition memory in rodents, and that 5-HT2A serotonin receptors are preferentially involved in stress- and drug-induced dopamine release in the rat medial prefrontal cortex.

Study details

Topics studied
Personality

Study characteristics
Theory Building

PDF of Do Psychedelics Change Beliefs?