Hallucinogen persisting perception disorder (HPPD) is characterized by visual disturbances that resemble psychedelic intoxication and linger after use has ceased. The most common substances precipitating HPPD, lysergic acid diethylamide (LSD) and psilocybin, are posited to do so via damage to serotonergic neurons involved in vision. Mr. N is a 37-year-old wi...
BackgroundClassic psychedelics, such as psilocybin and LSD, and other serotonin 2A receptor (5-HT2AR) agonists evoke acute alterations in perception and cognition. Altered thalamocortical connectivity has been hypothesized to underlie these effects, which is supported by some functional MRI (fMRI) studies. These studies have treated the thalamus as a unitary...
ABSTRACT Background Serotonin 2A receptor (5-HT 2AR ) agonist psychedelics including psilocybin and LSD (“classic” psychedelics) evoke acute alterations in perception and cognition. Altered thalamocortical connectivity has been proposed to underlie these effects, which is supported by some functional MRI (fMRI) studies. Likely due to sample size limitations,...
BackgroundLSD and psilocybin are increasingly used in phase I trials and evaluated as therapeutic agents for mental disorders. The phenomenon of reoccurring drug-like experiences after the acute substance effects have worn off was described for both substances and especially attributed to LSD. According to the DSM-V, the persisting and distressing manifestat...
This study seeks to understand the neural, cognitive and behavioral effects of low doses of psilocybin administered in the form of dried mushroom material (0.5 g of Psilocybe cubensis) consumed in natural settings following a placebo-controlled double-blind experimental design. Sub-threshold doses of serotonergic psychedelics are frequently consumed as cogni...
As source of sensory information, the body provides a sense of agency and self/non-self-discrimination. The integration of bodily states and sensory inputs with prior beliefs has been linked to the generation of bodily self-consciousness. The ability to detect surprising tactile stimuli is essential for the survival of an organism and for the formation of me...
This study was undertaken to investigate migraine prevalence in persons with hallucinogen persisting perception disorder (HPPD) presenting as visual snow syndrome (VSS). Persons with visual snow as a persisting symptom after illicit drug use (HPPD) were recruited via a Dutch consulting clinic for recreational drug use. A structured interview on (visual) perc...
ObjectivesClassic psychedelics (serotonin 2A receptor agonists) and dissociative hallucinogens (NMDA receptor antagonists), though differing in pharmacology, may share neuropsychological effects. These drugs, however, have undergone limited direct comparison. This report presents data from a double-blind, placebo-controlled within-subjects study comparing th...
The paper describes diagnostic criteria, clinical presentation and types of hallucinogen persisting perception disorder (HPPD), as well as current approaches to the treatment of this phenomenon using available scientific sources. Three case reports are also presented to demonstrate different types of this disorder. The first case report describes a 23-year o...
AL's leg was amputated resulting in phantom-limb pain (PLP). (1) When a volunteer placed her foot on or near the phantom - touching it evoked organized sensations in corresponding locations on AL's phantom. (2) Mirror-visual-feedback (MVF) relieved PLP, as did, "phantom massage". (3) Psilocybin-MVF pairing produced synergistic effects, complete elimination o...
Introduction: Cannabis has been historically classified as a hallucinogen. However, subjective cannabis effects do not typically include hallucinogen-like effects. Empirical reports of hallucinogen-like effects produced by cannabis in controlled settings, particularly among healthy research volunteers, are rare and have mostly occurred after administration o...
Serotonergic hallucinogens, such as lysergic acid diethylamide (LSD), psilocybin, and N,N-dimethyltryptamine (DMT), are famous for their capacity to temporally and profoundly alter an individual's visual experiences. These visual alterations show consistent attributes despite large inter- and intra-individual variances. Many reports document a common percept...
The classic serotonergic hallucinogens, or psychedelics, have the ability to profoundly alter perception and behavior. These can include visual distortions, hallucinations, detachment from reality, and mystical experiences. Some psychedelics, like LSD, are able to produce these effects with remarkably low doses of drug. Others, like psilocybin, have recently...
Hallucinogen-persisting perception disorder (HPPD) is a syndrome characterized by prolonged or reoccurring perceptual symptoms, reminiscent of acute hallucinogen effects. HPPD was associated with a broader range of LSD (lysergic acid diethylamide)-like substances, cannabis, methylenedioxymethamphetamine (MDMA), psilocybin, mescaline, and psychostimulants. Th...
BackgroundSalvinorin-A is a terpene found in the leaves of the plant Salvia divinorum. When administered to humans, salvinorin-A induces an intense but short-lasting modified state of awareness, sharing features with those induced by the classical serotonin-2A receptor agonist psychedelics. However, unlike substances such as psilocybin or mescaline, salvinor...
Psychedelics (serotonergic hallucinogens) are powerful psychoactive substances that alter perception and mood and affect numerous cognitive processes. They are generally considered physiologically safe and do not lead to dependence or addiction. Their origin predates written history, and they were employed by early cultures in many sociocultural and ritual c...
Studies have shown that both serotonin and glutamate receptor systems play a crucial role in the mechanisms underlying drug-induced synesthesia. The specific nature of these mechanisms, however, continues to remain elusive. Here we propose two distinct hypotheses for how synesthesia triggered by hallucinogens in the serotonin-agonist family may occur. One hy...
The development of pharmacological magnetic resonance imaging (phMRI) has presented the opportunity for investigation of the neurophysiological effects of drugs in vivo. Psilocin, a hallucinogen metabolised from psilocybin, was recently reported to evoke brain region-specific, phMRI signal changes in humans. The present study investigated the effects of psil...
Ego-disturbances have been a topic in schizophrenia research since the earliest clinical descriptions of the disorder. Manifesting as a feeling that one's "self," "ego," or "I" is disintegrating or that the border between one's self and the external world is dissolving, "ego-disintegration" or "dissolution" is also an important feature of the psychedelic exp...
Psilocybin is a substance of natural origin, occurring in hallucinogenic mushrooms (most common in the Psilocybe family). After its synthesis in 1958 research began on its psychoactive properties, particularly strong effects on visual perception and spatial orientation. Due to the very broad spectrum of psilocybin effects research began on the different rang...
