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.
Cortex; a journal devoted to the study of the nervous system and behavior
February 1, 2013
Etzel Cardeña, Peter Jönsson, Devin B. Terhune et al.
151 citations
After a hypnotic induction, people who are highly or moderately hypnotizable often report spontaneous changes in consciousness, but few studies have controlled for the demands of specific suggestions or examined the brain activity underlying these experiences. In a neurophenomenological study of 37 individuals with high, medium, and low hypnotizability, participants reported their depth and spontaneous experiences at baseline, after induction, and after rest periods, while EEG measured brain activity. Perceived hypnotic depth increased substantially after induction, especially among highly and moderately hypnotizable individuals, but remained almost unchanged among those low in hypnotizability.
Frontiers in Psychology
January 1, 2013
David 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.
The American journal of clinical hypnosis
October 1, 2016
Devin B. Terhune, Etzel Cardeña
53 citations
Inductions are widely considered the starting point of hypnosis, yet their actual role is poorly understood and often oversimplified. Drawing on research into suggestibility, spontaneous experience, brain activity, and cognition, this article argues that the value of inductions is more nuanced and uncertain than commonly assumed. Some components of standard inductions clearly boost suggestibility, while others show no clear benefit. The effect of inductions on suggestibility varies depending on the type of suggestion and how it is measured, and the reasons for this variability remain unknown. Examining these effects through the lens of individual differences in high hypnotic suggestibility and componential models may open new research directions. The article advocates for practical, theory-driven optimization of inductions.
Neuropsychologia
April 5, 2016
Devin B. Terhune, David 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.
PCN reports : psychiatry and clinical neurosciences
December 1, 2023
Simon Ruffell, Max Crosland-Wood, Rob Palmer et al.
37 citations
Ayahuasca, a psychedelic plant brew from the Amazon made from Banisteriopsis caapi vine and a DMT-containing plant like Psychotria viridis, has attracted growing interest since the year 2000. This review covers its history, pharmacology, and the phenomenological responses it produces. Anecdotal reports range from positive to accounts of physical and psychological harm. The authors discuss effects on personality and mental health, and examine phenomenological analyses of the experience. They conclude that ayahuasca is a promising psychedelic agent deserving more empirical research into its neurochemical mechanisms and potential therapeutic use.
Seeing and Perceiving
January 1, 2012
David Luke, Devin B. Terhune, Ross Friday
11 citations
Synaesthesia, a condition where stimulation of one sense triggers perception in another, is frequently induced by psychedelic substances that act on the serotonin system, such as LSD and psilocybin. A survey of recreational drug users found that these serotonergic agonists commonly cause synaesthetic experiences and can also intensify existing synaesthesia in those who have the congenital form. The findings suggest that the serotonergic system plays a key role in the neurobiology of synaesthesia, offering a pathway to understand broader questions about consciousness and how the brain binds sensory information.
Biological Psychiatry Global Open Science
July 1, 2025
Benjamin Brake, Lillian Wieder, Natasha Hughes et al.
5 citations
Dissociative states—disruptions in awareness and perception—occur across many psychiatric conditions and can be modeled in the lab. A meta-analysis of 123 studies (6,692 individuals) measured state dissociation using a standardized scale. At baseline, the largest effects were in dissociative and complex subtypes of posttraumatic stress disorder. In controlled experiments, mirror gazing and several drugs, particularly ketamine and cannabis, induced dissociation as high as or higher than that seen in PTSD. Results were highly variable across studies but not explained by methodological differences. These findings validate experimental methods for inducing dissociation and inform monitoring of adverse events in drug-based interventions.
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.
Journal of psychopharmacology (Oxford, England)
July 1, 2018
Clément E Lemercier, Devin B. Terhune
Psychedelics and hypnosis share overlapping applications and neurophenomenological features in treating psychopathologies, yet the potential of suggestion to shape psychedelic experiences for better therapeutic outcomes has been underexplored. This review compares the phenomenological and neurophysiological similarities and differences between psychedelic states and hypnosis, drawing on recent research and early studies of their combined use. Commonalities and differences suggest that coupling the two could enhance psychotherapy. The authors propose research paths for integrating hypnosis at different stages of psychedelic-assisted psychotherapy—preparation, acute phase, and follow-up—to guide and integrate experiences. Harnessing suggestion may increase positive responses, including mystical-type experiences, thereby boosting therapeutic efficacy.