Psychopharmacology
November 26, 2018
Steliana Yanakieva, Naya Polychroni, Neiloufar Family et al.
169 citations
Microdoses of LSD (5, 10, and 20 μg) caused older adults to over-reproduce time intervals of 2000 milliseconds and longer, with the strongest effect at 10 μg. This temporal dilation occurred without noticeable changes in perception, mentation, or concentration, and was independent of any subjective drug effects. The findings suggest that LSD can directly alter interval timing at doses too low to produce conscious psychedelic effects, indicating a dissociation between neurochemical influences on time perception and altered states of consciousness.
Frontiers in Psychology
January 1, 2013
David P. Luke, Devin B. Terhune
81 citations
A review of published studies finds consistent evidence that serotonin agonists can temporarily produce synaesthesia, a condition where senses blend, such as seeing sounds. However, the research has many methodological flaws and little experimental work has been done. While the findings point to the serotonergic system's role in synaesthesia, the limitations prevent firm conclusions about whether chemicals truly induce genuine synaesthesia.
Cortex
June 6, 2008
Devin B. Terhune
60 citations
About 70% of people who have had an out-of-body experience (OBE) report that the experience included visual content. Individuals who saw something during their OBE scored higher on measures of preference for object-based visual thinking and weak synaesthesia than those who reported no visual content. Weak synaesthesia was the stronger factor distinguishing the two groups. The findings support a synaesthetic model in which visual hallucinations during OBEs arise from a cognitive blending of non-visual sensory cues, possibly due to hyperconnectivity between brain areas handling body representation and visual processing.
Neuropsychologia
April 5, 2016
Devin B. Terhune, David P. Luke, Mendel Kaelen et al.
45 citations
Lysergic acid diethylamide (LSD) induces synaesthesia-like experiences in non-synaesthetes, but these experiences do not meet two key criteria for genuine synaesthesia: consistency of stimulus-colour associations over time and inducer specificity. In a placebo-controlled pilot study, participants reported more spontaneous synaesthesia-like experiences under LSD compared to placebo, yet their colour responses to standardized graphemes and sounds did not differ across conditions in consistency or specificity. Individual differences in absorption propensity were linked to some effects. The findings suggest that LSD-induced synaesthesia-like experiences are not equivalent to genuine synaesthesia.
February 21, 2023
Simon Ruffell, Nigel Netzband, WaiFung Tsang et al.
3 citations
preprint
Ayahuasca, a psychedelic brew from the Amazon Rainforest made from the Banisteriopsis caapi vine and a DMT-containing plant like Psychotria viridis, has seen a surge in global interest since 2000. This review covers its history, pharmacology, and phenomenological effects, as well as clinical applications. Tourists increasingly travel to the Amazon to consume it, and retreat centers offering plant medicine have become a thriving business. Anecdotal reports range from evangelical accounts to stories of physical and psychological harm. The brew shows promise as a psychedelic agent warranting more empirical research into its neurochemical mechanisms and therapeutic uses.
medRxiv
September 10, 2024
Benjamin Brake, Lillian Wieder, Natasha Hughes et al.
2 citations
preprint
Dissociative states—disruptions in awareness and perception—occur across many psychiatric disorders and can be experimentally induced. This meta-analysis of 123 studies (6,692 individuals) measured state dissociation using a standard scale. At baseline, the largest effects were in dissociative and complex subtypes of post-traumatic stress disorder (PTSD-DC). In controlled experiments, mirror-gazing and several drugs (especially ketamine and cannabis) produced dissociation levels as high as or higher than baseline PTSD-DC. Effect sizes varied widely but were not consistently linked to study methods. The findings confirm that dissociation can be reliably modeled in the lab, with implications for measuring side effects and predicting outcomes in drug-based treatments.
Madeline Victore Stein, Devin B. Terhune
1 citation
preprint
Growing excitement about psychedelics in media and science often overlooks the influence of suggestion—where expectations and beliefs shape outcomes. Suggestion can distort experimental research on psychedelics' neurocognitive effects, yet it may also enhance therapeutic results when used deliberately. The authors call for greater attention to suggestion as both a source of bias and a potential tool to maximize benefits in psychedelic-assisted therapy.
medRxiv Preprint Server
May 31, 2026
Madeline V. Stein, Matt Butler, Sarah Chapman et al.
preprint
Context alone can produce psychedelic-like effects, even without an active drug. In a placebo experiment, 78 healthy participants inhaled inert medical air. When told it was nitrous oxide, they reported increased altered states of consciousness, ego dissolution, dissociation, and side effects, compared to when the gas was correctly identified as air. Time perception was not significantly affected. The strength of placebo-induced effects was predicted by individual traits of responsiveness to verbal suggestion and absorption. These results demonstrate that the context of drug administration plays a causal role in shaping psychedelic experiences.