Biol Psychiatry
May 25, 2018
Philipp Sterzer, Rick A. Adams, Paul Fletcher et al.
901 citations
Psychosis may stem from altered predictive coding in the brain, where prior beliefs are combined with sensory signals to interpret the world. The canonical account suggests that weakened prior beliefs relative to sensory data lead to maladaptive inferences. However, evidence is mixed: some studies find weakened priors, others stronger priors. Hallucinations and delusions may involve distinct predictive coding alterations. Challenges include non-uniform deficits across sensory modalities, hierarchical processing where lower and higher levels interact non-linearly, and the role of active inference—anticipating how actions affect sensations. Considering these complexities could reconcile conflicting findings and yield a more comprehensive framework for psychosis.
Schizophrenia Bulletin
July 21, 2023
Predrag Petrović, Philipp Sterzer
42 citations
Delusions in psychotic disorders are hard to reconcile with the predictive processing (PP) framework, which suggests psychosis involves reduced weighting of prior beliefs relative to sensory data—yet delusions are highly resistant to change. This paradox can be resolved by a hierarchical PP model: reduced weighting of low-level priors may be compensated by increased influence of higher-order beliefs, including delusional beliefs, which then shape perception and resist contradictory evidence. A review of experimental evidence supports decreased weighting of low-level priors and increased weighting of high-level priors in both delusional and delusion-prone individuals. The prefrontal cortex is highlighted as a neural basis for this increased weighting of high-level priors, with clinical implications discussed.
Journal of Affective Disorders
January 26, 2024
Ludwig Honk, Cecilia U.D. Stenfors, Simon B. Goldberg et al.
41 citations
Using data from nearly 10,000 adults in the US and UK, psychedelic use over a two-month period was not linked to changes in psychotic symptoms overall. However, among people with a personal or family history of bipolar disorder, psychedelic use was associated with an increase in symptoms. Conversely, those with a personal history of psychotic disorders experienced a decrease in symptoms. These findings suggest that the effects of psychedelics on psychotic symptoms depend on an individual's psychiatric history.
Scientific Reports
July 23, 2021
Alexander V. Lebedev, Kasim Acar, Benjamín Garzón et al.
19 citations
Psychedelic drug use shows only a weak association with psychosis-like symptoms, largely explained by psychiatric comorbidities and use of other psychoactive substances. In a study of 1,032 adults (701 healthy young adults aged 18–35), psychedelic users had slightly higher schizotypy scores, but the effect was small and not significant after controlling for other drug use. Experimental testing in 39 subjects found that greater lifetime psychedelic exposure was linked to better evidence integration and heightened fear responses to instructed knowledge in a learning task, suggesting possible therapeutic effects on flexibility and aversive learning in non-psychotic populations.
Scientific Reports
September 30, 2023
Alexander V. Lebedev, Kasim Acar, Otilia Horntvedt et al.
9 citations
People who have used psychedelics are moderately more likely to endorse alternative facts and to believe that facts are politically influenced, compared with people who have never used them. This association held after accounting for demographics, psychiatric conditions, and other drug use. No link was found between psychedelic use and preferring intuition over evidence when verifying facts. Among other drugs examined, only alcohol showed a negative association with belief in alternative facts. The findings suggest that psychedelic use correlates with non-conformist thinking styles, which may stem from the drugs' psychological effects or from a shared trait predisposing people to unconventional beliefs and illicit substance use.
Int J Drug Policy
December 13, 2025
Michelle Olofsson, Walter Osika, Simon B. Goldberg et al.
2 citations
A cross-sectional survey of 3,168 U.S. adults with lifetime psychedelic use found that most (87.9%) reported no difficulties. Among those who did, 6.4% experienced post-acute difficulties lasting more than one day, and 1.3% for more than one year. The most common difficulties were general anxiety, negative changes in self-concept, and social disconnection. Childhood adversity was associated with higher odds of psychedelic-related difficulties: individuals with 2, 3, or 4 or more adverse childhood experiences had roughly double to nearly triple the odds of difficulties compared to those with none. Those with 4 or more ACEs also had higher odds of difficulties persisting beyond one day or one week.
May 31, 2022
Predrag Petrović, Jovana Vunduk
2 citations
Mushroom-forming fungi produce a wide range of unique metabolites, including polysaccharides, terpenoids, polyketides, and amino compounds, that exhibit various biological effects. The most studied application is cancer treatment, where mushrooms provide compounds with direct antitumor effects and immunomodulating polysaccharides like β-glucans that stimulate the immune system against cancer cells. Clinically proven glucan-based products such as lentinan from Lentinula edodes and PSK from Trametes versicolor benefit certain cancer types. Mushrooms also yield potent cytotoxic compounds (illudins, clitocine, ganoderic acids) and antimicrobial agents, with pleuromutilin leading to new drugs approved for human use. Psychedelic mushrooms and psilocybin are studied as therapies for depression, and mushroom consumption is linked to improved sugar and lipid metabolism, though claims about vitamin content may be overstated; production can be manipulated to increase compounds like vitamin D.