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At least 19 recordsLinked to original sources

PubMed2006

Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance.

RATIONALE: Although psilocybin has been used for centuries for religious purposes, little is known scientifically about its acute and persisting effects. OBJECTIVES: This double-blind study evaluated the acute and longer-term psychological effects of a high dose of psilocybin relative to a comparison compound administered under comfortable, supportive conditions. MATERIALS AND METHODS: The participants were hallucinogen-naïve adults reporting regular participation in religious or spiritual activities. Two or three sessions were conducted at 2-month intervals. Thirty volunteers received orally administered psilocybin (30 mg/70 kg) and methylphenidate hydrochloride (40 mg/70 kg) in counterbalanced order. To obscure the study design, six additional volunteers received methylphenidate in the first two sessions and unblinded psilocybin in a third session. The 8-h sessions were conducted individually. Volunteers were encouraged to close their eyes and direct their attention inward. Study monitors rated volunteers' behavior during sessions. Volunteers completed questionnaires assessing drug effects and mystical experience immediately after and 2 months after sessions. Community observers rated changes in the volunteer's attitudes and behavior. RESULTS: Psilocybin produced a range of acute perceptual changes, subjective experiences, and labile moods including anxiety. Psilocybin also increased measures of mystical experience. At 2 months, the volunteers rated the psilocybin experience as having substantial personal meaning and spiritual significance and attributed to the experience sustained positive changes in attitudes and behavior consistent with changes rated by community observers. CONCLUSIONS: When administered under supportive conditions, psilocybin occasioned experiences similar to spontaneously occurring mystical experiences. The ability to occasion such experiences prospectively will allow rigorous scientific investigations of their causes and consequences.

Adult↗

PubMed1999

5-HT modulation of dopamine release in basal ganglia in psilocybin-induced psychosis in man--a PET study with [11C]raclopride.

The modulating effects of serotonin on dopamine neurotransmission are not well understood, particularly in acute psychotic states. Positron emission tomography was used to examine the effect of psilocybin on the in vivo binding of [11C]raclopride to D2-dopamine receptors in the striatum in healthy volunteers after placebo and a psychotomimetic dose of psilocybin (n = 7). Psilocybin is a potent indoleamine hallucinogen and a mixed 5-HT2A and 5-HT1A receptor agonist. Psilocybin administration (0.25 mg/kg p.o.) produced changes in mood, disturbances in thinking, illusions, elementary and complex visual hallucinations and impaired ego-functioning. Psilocybin significantly decreased [11C]raclopride receptor binding potential (BP) bilaterally in the caudate nucleus (19%) and putamen (20%) consistent with an increase in endogenous dopamine. Changes in [11C]raclopride BP in the ventral striatum correlated with depersonalization associated with euphoria. Together with previous reports of 5-HT receptor involvement in striatal dopamine release, it is concluded that stimulation of both 5-HT2A and 5-HT1A receptors may be important for the modulation of striatal dopamine release in acute psychoses. The present results indirectly support the hypothesis of a serotonin-dopamine dysbalance in schizophrenia and suggest that psilocybin is a valuable tool in the analysis of serotonin-dopamine interactions in acute psychotic states.

Adult↗

PubMed2006

Effects of psilocybin on time perception and temporal control of behaviour in humans.

Hallucinogenic psilocybin is known to alter the subjective experience of time. However, there is no study that systematically investigated objective measures of time perception under psilocybin. Therefore, we studied dose-dependent effects of the serotonin (5-HT)2A/1A receptor agonist psilocybin (4-phosphoryloxy-N, N-dimethyltryptamine) on temporal processing, employing tasks of temporal reproduction, sensorimotor synchronization and tapping tempo. To control for cognitive and subjective changes, we assessed spatial working memory and conscious experience. Twelve healthy human volunteers were tested under placebo, medium (115 microg/kg), and high (250 microg/kg) dose conditions, in a double-blind experimental design. Psilocybin was found to significantly impair subjects' ability to (1) reproduce interval durations longer than 2.5 sec, (2) to synchronize to inter-beat intervals longer than 2 sec and (3) caused subjects to be slower in their preferred tapping rate. These objective effects on timing performance were accompanied by working-memory deficits and subjective changes in conscious state, namely increased reports of 'depersonalization' and 'derealization' phenomena including disturbances in subjective 'time sense.' Our study is the first to systematically assess the impact of psilocybin on timing performance on standardized measures of temporal processing. Results indicate that the serotonin system is selectively involved in duration processing of intervals longer than 2 to 3 seconds and in the voluntary control of the speed of movement. We speculate that psilocybin's selective disruption of longer intervals is likely to be a product of interactions with cognitive dimensions of temporal processing -presumably via 5-HT2A receptor stimulation.

Adult↗

PubMed2006

Response of cluster headache to psilocybin and LSD.

The authors interviewed 53 cluster headache patients who had used psilocybin or lysergic acid diethylamide (LSD) to treat their condition. Twenty-two of 26 psilocybin users reported that psilocybin aborted attacks; 25 of 48 psilocybin users and 7 of 8 LSD users reported cluster period termination; 18 of 19 psilocybin users and 4 of 5 LSD users reported remission period extension. Research on the effects of psilocybin and LSD on cluster headache may be warranted.

Adult↗

PubMed2006

The determination of psilocin and psilocybin in hallucinogenic mushrooms by HPLC utilizing a dual reagent acidic potassium permanganate and tris(2,2'-bipyridyl)ruthenium(II) chemiluminescence detection system.

This paper describes a procedure for the determination of psilocin and psilocybin in mushroom extracts using high-performance liquid chromatography with postcolumn chemiluminescence detection. A number of extraction methods for psilocin and psilocybin in hallucinogenic mushrooms were investigated, with a simple methanolic extraction being found to be most effective. Psilocin and psilocybin were extracted from a variety of hallucinogenic mushrooms using methanol. The analytes were separated on a C12 column using a (95:5% v/v) methanol:10 mM ammonium formate, pH 3.5 mobile phase with a run time of 5 min. Detection was realized through a dual reagent chemiluminescence detection system of acidic potassium permanganate and tris(2,2'-bipyridyl)ruthenium(II). The chemiluminescence detection system gave improved detectability when compared with UV absorption at 269 nm, with detection limits of 1.2 x 10(-8) and 3.5 x 10(-9) mol/L being obtained for psilocin and psilocybin, respectively. The procedure was applied to the determination of psilocin and psilocybin in three Australian species of hallucinogenic mushroom.

Agaricales↗

PubMed2005

Using psilocybin to investigate the relationship between attention, working memory, and the serotonin 1A and 2A receptors.

Increasing evidence suggests a link between attention, working memory, serotonin (5-HT), and prefrontal cortex activity. In an attempt to tease out the relationship between these elements, this study tested the effects of the hallucinogenic mixed 5-HT1A/2A receptor agonist psilocybin alone and after pretreatment with the 5-HT2A antagonist ketanserin. Eight healthy human volunteers were tested on a multiple-object tracking task and spatial working memory task under the four conditions: placebo, psilocybin (215 microg/kg), ketanserin (50 mg), and psilocybin and ketanserin. Psilocybin significantly reduced attentional tracking ability, but had no significant effect on spatial working memory, suggesting a functional dissociation between the two tasks. Pretreatment with ketanserin did not attenuate the effect of psilocybin on attentional performance, suggesting a primary involvement of the 5-HT1A receptor in the observed deficit. Based on physiological and pharmacological data, we speculate that this impaired attentional performance may reflect a reduced ability to suppress or ignore distracting stimuli rather than reduced attentional capacity. The clinical relevance of these results is also discussed.

Adult↗

PubMed1989

Handling of psilocybin and psilocin by everted sacs of rat jejunum and colon.

Psilocybin and psilocin at luminal concentrations of about 20 nmol/ml were incubated aerobically with everted sacs from rat jejunum and colon. When incubation was terminated, samples of the lumen and blood side solutions and of the intestinal tissue were analyzed for parent drug and metabolites by HPLC using a multidetector system. Both sacs caused hydrolysis of psilocybin to psilocin, but the rate was much faster in the jejunum than in the colon. Tissue uptake of intact psilocybin was negligible or absent, and no transfer to the contraside of the parent drug could be demonstrated. In contrast, psilocin, whether formed by hydrolysis or added as a substrate, was well taken up by both intestinal segments and transferred to the blood side. In the colonic psilocybin experiments, this uptake and transfer was limited by a low hydrolytic rate. The results indicate that psilocybin under in vivo conditions is absorbed predominantly as psilocin. No further metabolism of either drug was observed, as opposed to the complex metabolism pattern that has been reported for serotonin, a close chemical relative to psilocin.

Animals↗

PubMed1997

Determination of psilocybin in Psilocybe semilanceata by capillary zone electrophoresis.

A capillary zone electrophoretic (CZE) method was developed for the rapid determination of psilocybin in Psilocybe semilanceata. Following a simple two step extraction with 3.0+2.0 ml methanol, the hallucinogenic compound was effectively separated from matrix components by CZE utilizing a 10 mM borate-phosphate running buffer adjusted to pH 11.5. The identity of psilocybin was confirmed by migration time information and by UV spectra, while quantitation was accomplished utilizing barbital as internal standard. The calibration curve for psilocybin was linear within 0.01-1 mg/ml, while intra-day and inter-day variations of quantitative data were 0.5 and 2.5% R.S.D., respectively. In addition to psilocybin, the method was also suitable for the determination of the structurally related compound baeocystin.

Agaricales↗

PubMed2004

Psilocybin impairs high-level but not low-level motion perception.

The hallucinogenic serotonin(1A&2A) agonist psilocybin is known for its ability to induce illusions of motion in otherwise stationary objects or textured surfaces. This study investigated the effect of psilocybin on local and global motion processing in nine human volunteers. Using a forced choice direction of motion discrimination task we show that psilocybin selectively impairs coherence sensitivity for random dot patterns, likely mediated by high-level global motion detectors, but not contrast sensitivity for drifting gratings, believed to be mediated by low-level detectors. These results are in line with those observed within schizophrenic populations and are discussed in respect to the proposition that psilocybin may provide a model to investigate clinical psychosis and the pharmacological underpinnings of visual perception in normal populations.

Adult↗

PubMed2026

Psilocybin prevents chemotherapy-induced peripheral neuropathy through mitochondrial trafficking preservation.

Chemotherapy-induced peripheral neuropathy (CIPN) is a disabling, often irreversible toxicity that affects millions of patients, limits life-saving cancer therapy, and lacks proven treatment. In this work, we show that as little as two doses of psilocybin before chemotherapy durably prevented the onset of CIPN across platinum- and taxane-based models, including repeated chemotherapy cycles, without impairing antitumor efficacy. Peripherally, psilocybin maintained tactile sensitivity and intraepidermal nerve fiber endings through axonal mitochondrial trafficking and distribution preservation, through the TrkB-Akt-PAK5-MAP2-KIF5B pathway and remobilization of syntaphilin-anchored mitochondria. Centrally, it normalized medial prefrontal cortical synaptic activity and cortical alpha and beta electroencephalography power. This stabilization of peripheral axonal energy balance establishes psilocybin as a first-in-class prophylactic agent for CIPN while also preserving central neural function. Given psilocybin's established safety, these discoveries support clinical evaluation as a strategy to prevent CIPN.

Animals↗

PubMed2006

Safety, tolerability, and efficacy of psilocybin in 9 patients with obsessive-compulsive disorder.

BACKGROUND: Anecdotal reports suggest that psychedelic agents may relieve symptoms of obsessive-compulsive disorder (OCD). This modified double-blind study investigated the safety, tolerability, and clinical effects of psilocybin, a potent 5-HT(1A) and 5-HT(2A/2C) agonist, in patients with OCD. METHOD: Nine subjects with DSM-IV-defined OCD and no other current major psychiatric disorder participated in up to 4 single-dose exposures to psilocybin in doses ranging from sub-hallucinogenic to frankly hallucinogenic. Low (100 microg/kg), medium (200 microg/kg), and high (300 microg/kg) doses were assigned in that order, and a very low dose (25 microg/kg) was inserted randomly and in double-blind fashion at any time after the first dose. Testing days were separated by at least 1 week. Each session was conducted over an 8-hour period in a controlled environment in an outpatient clinic; subjects were then transferred to a psychiatric inpatient unit for overnight observation. The Yale-Brown Obsessive Compulsive Scale (YBOCS) and a visual analog scale measuring overall obsessive-compulsive symptom severity were administered at 0, 4, 8, and 24 hours post-ingestion. The Hallucinogen Rating Scale was administered at 8 hours, and vital signs were recorded at 0, 1, 4, 8, and 24 hours after ingestion. The study was conducted from November 2001 to November 2004. RESULTS: Nine subjects were administered a total of 29 psilocybin doses. One subject experienced transient hypertension without relation to anxiety or somatic symptoms, but no other significant adverse effects were observed. Marked decreases in OCD symptoms of variable degrees were observed in all subjects during 1 or more of the testing sessions (23%-100% decrease in YBOCS score). Repeated-measures analysis of variance for all YBOCS values revealed a significant main effect of time on Wilks lambda (F = 9.86, df = 3,3; p = .046), but no significant effect of dose (F = 2.25, df = 3,3; p = .261) or interaction of time and dose (F = 0.923, df = 9,45; p = .515). Improvement generally lasted past the 24-hour timepoint. CONCLUSIONS: In a controlled clinical environment, psilocybin was safely used in subjects with OCD and was associated with acute reductions in core OCD symptoms in several subjects.

Adult↗

PubMed1990

[Hallucinogenic psilocybine containing mushrooms. Toxins contained in Danish wild mushrooms].

A number of the wild Danish mushrooms contain the hallucinogenic agent psilocybin which resembles LSD in many ways. The commonest of these are the "liberty cap" or "magic mushrooms" (Psilocybe semilanceata). On the basis of experience from USA and western Europa, increase in employment of this mushrooms as a hallucinogenic intoxicant may be anticipated in Denmark. The history, epidemiology, botany and pharmacology of the mushroom are reviewed. Clinical pictures and treatment are described for: 1) Acute poisoning with psilocybin-containing fungi, 2) Late sequelae of consumption of psilocybin-containing fungi and 3) Poisoning with more poisonous fungi on account of incorrect identification. General practitioners, duty roster doctors, doctors in casualty departments and in acute psychiatric departments should be aware of these problems. Intoxication with psilocybin may be confused with panic anxiety or euphoria in persons with mydriasis and other sympathomimetic symptoms. The possibility of more serious mushroom poisoning on account of incorrect identification should be borne in mind.

Denmark↗

PubMedDate not supplied

The occurrence of psilocybin in Gymnopilus species.

An accidental case of mushroom poisoning led to the detection of psilocybin in Gymnopilus validipes (Cortinariaceae). This compound was subsequently isolated (0.12% yield) by anion exchange and cellulose chromatography. Eighteen additional species of Gymnopilus were screened by a method capable of detecting 0.0004% psilocybin in dried carpophores. Psilocybin was detected in G. aeruginosus, G. luteus, G. viridans and G. spectabilis. The latter species has been previously reported to be hallucinogenic. This is the first report of psilocybin from this genus.

Agaricales↗

PubMed1982

Psilocybin as a discriminative stimulus: lack of specificity in an animal behavior model for 'hallucinogens'.

Fifteen rats were trained to discriminate between the tryptamine hallucinogen psilocybin (4-phosphoryloxy-N,N-dimethyltryptamine; 1.0 mg/kg) and saline in a two-lever choice task. Dose-response and time-response curves were obtained. The psilocybin cue generalized to psilocin (the dephosphorylated congener of psilocybin) and to the prototypical indoleamine hallucinogen LSD, but not to the phenylethylamine hallucinogen mescaline. These results indicate that the hallucinogenic effects of these drugs in humans may not be identical with their discriminative stimulus functions in animals, and that these four compounds may not be members of a single drug class. The term 'hallucinogen' may thus be a misnomer in the context of drug discrimination studies in nonhumans.

Animals↗

PubMed1977

Psilocybin: biphasic dose-response effects on the acoustic startle reflex in the rat.

The startle reflex was measured in 7 groups of 10 rats each after intraperitoneal injection of saline or 0.25, 0.50, 0.75, 1.0, 2.0, 4.0 or 8.0 mg/kg psilocybin. Low doses (0.75-2.0 mg/kg) increased startle amplitude whereas high doses (4.0-8.0 mg/kg) depressed startle. Selected low (0.71 mg/kg) or high (5.70 mg/kg) doses of psilocin also had a biphasic dose-response effect on startle comparable in magnitude to equimolar doses of psilocybin. This biphasic dose-response relationship of the indole hallucinogen, psilocybin, on startle is consistent with the hypothesis that startle is increased when the firing rates of midbrain raphe neurons are selectively inhibited but is depressed when neurons postsynaptic to raphe cells are also inhibited.

Acoustic Stimulation↗

PubMed1982

Psilocybin and psilocin levels in twenty species from seven genera of wild mushrooms in the Pacific Northwest, U.S.A.

The analysis of twenty species from seven genera of Pacific Northwest mushrooms revealed psilocybin (and in some cases psilocin as well) in seven species from three genera. The species found to contain psilocybin (and psilocin) varied from one collection to another by more than a factor of seven in amount present. Total psilocybin and psilocin levels in species known to be in use for recreational and entheogenic purposes varied from 0.1% by dry weight up to a high of nearly 2% by dry weight.

Basidiomycota↗

PubMed2026

Blinding integrity in psychedelic research: Evidence from a comparative randomized controlled trial of psilocybin, MDMA, and methylphenidate in healthy volunteers.

Maintaining effective blinding is a major methodological challenge in psychedelic research. This study provides a comprehensive evaluation of blinding integrity in 120 healthy volunteers who received either psilocybin, MDMA, or methylphenidate (active placebo) in a double-blind, randomized controlled trial. Using a multi-level assessment incorporating forced-choice substance guesses, certainty ratings, decision factors, and subjective substance effects, the analyses characterize blinding integrity and its relation to the substance experience. Results indicate that overall blinding was insufficient, with psilocybin showing the highest rates of functional unblinding, MDMA moderate levels, and methylphenidate the lowest. As an active placebo, methylphenidate provided more effective blinding for MDMA than for psilocybin. Incorporating certainty levels of substance guesses revealed a more differentiated pattern, with lower functional unblinding rates. Decision factors and subjective substance experiences were associated with phenomenological substance effects. Prior substance experiences did not influence accuracy of forced-choice substance guesses. These findings provide empirical guidance for the design and reporting of blinding procedures in psychedelic trials and underscore the value of systematic, multi-level assessment of blinding integrity.

Humans↗

PubMed1997

Positron emission tomography and fluorodeoxyglucose studies of metabolic hyperfrontality and psychopathology in the psilocybin model of psychosis.

The effects of the indolehallucinogen psilocybin, a mixed 5-HT2 and 5-HT1 agonist, on regional cerebral glucose metabolism were investigated in 10 healthy volunteers with PET and [F-18]-fluorodeoxyglucose (FDG) prior to and following a 15- or 20-mg dose of psilocybin. Psychotomimetic doses of psilocybin were found to produce a global increase in cerebral metabolic rate of glucose (CMRglu) with significant and most marked increases in the frontomedial and frontolateral cortex (24.3%), anterior cingulate (24.9%), and temporomedial cortex (25.3%). Somewhat smaller increases of CMRglu were found in the basal ganglia (18.5%), and the smallest increases were found in the sensorimotor (14.7%) and occipital cortex (14.4%). The increases of CMRglu in the prefrontal cortex, anterior cingulate, temporomedial cortex, and putamen correlated positively with psychotic symptom formation, in particular with hallucinatory ego disintegration. The present data suggest that excessive 5-HT2 receptor activation results in a hyperfrontal metablic pattern that parallels comparable metabolic findings associated with acute psychotic episodes in chronic schizophrenics and contrasts with the hypofrontality in chronic schizophrenic patients.

Adult↗