Current treatments for addiction are frequently ineffective. Hallucinogenic therapy has been indicated as helpful for a range of substance use disorders, yet this approach remains understudied and publicly unavailable. It is nonetheless a promising treatment, which has significant, long-term beneficial effects with single doses and a profile characterized by...
Psychotomimetics like the N-methyl-D-aspartate receptor (NMDAR) antagonist ketamine and the 5-hydroxytryptamine2A receptor (5-HT(2A)R) agonist psilocybin induce psychotic symptoms in healthy volunteers that resemble those of schizophrenia. Recent theories of psychosis posit that aberrant encoding of prediction errors (PE) may underlie the expression of psych...
BackgroundThe OAV questionnaire has been developed to integrate research on altered states of consciousness (ASC). It measures three primary and one secondary dimensions of ASC that are hypothesized to be invariant across ASC induction methods. The OAV rating scale has been in use for more than 20 years and applied internationally in a broad range of researc...
The history of serotonin research is closely related to the study of hallucinogenic drugs that function as agonists at serotonin-2A receptors. The fundamental idea that psychotic states seen in psychiatric disorders such as schizophrenia might be attributable, in part, to abnormalities in serotonergic systems began with the almost simultaneous discovery of l...
RationaleBinocular rivalry occurs when different images are simultaneously presented to each eye. During continual viewing of this stimulus, the observer will experience repeated switches between visual awareness of the two images. Previous studies have suggested that a slow rate of perceptual switching may be associated with clinical and drug-induced psycho...
Binocular rivalry occurs when different images are presented simultaneously to corresponding points within the left and right eyes. Under these conditions, the observer's perception will alternate between the two perceptual alternatives. Motivated by the reported link between the rate of perceptual alternations, symptoms of psychosis and an incidental observ...
BackgroundPrevious studies indicate that mismatch negativity (MMN)-a preattentive auditory event-related potential (ERP)-depends on NMDA receptor (NMDAR) functioning. To explore if the strength of MMN generation reflects the functional condition of the NMDAR system in healthy volunteers, we analyzed correlations between MMN recorded before drug administratio...
Hallucinogenic drug-induced states are considered as models for acute schizophrenic disorders (experimental psychoses). In a double-blind study with healthy volunteers we investigated the influence of the serotonergic hallucinogen psilocybin, the ecstasy-like drug 3,4-methylenedioxyethylamphetamine (MDE), the stimulant d- methamphetamine and placebo on cover...
Increasing evidence from neuroimaging and behavioral studies suggests that functional disturbances within cortico-striato-thalamic pathways are critical to psychotic symptom formation in drug-induced and possibly also naturally occurring psychoses. Recent basic and clinical research with psychotomimetic drugs, such as the N-methyl-D-aspartate (NMDA) glutamat...
Schizophrenic patients exhibit deficits in indices of sensorimotor gating, such as habituation and prepulse inhibition (PPI) of the startle reflex. Hallucinogenic drug-induced states are putative models for the early and acute stages of schizophrenic and schizophrenia-spectrum disorders. Hallucinogenic drugs have been shown to disrupt PPI and/or retard habit...
Recent research into the pharmacological mechanism of hallucinogens (LSD, psilocybin) and dissociative anesthetics (PCP, ketamine) suggest that multiple neurotransmitter systems are involved in drug-induced and possibly also in naturally occurring psychoses. Specifically, animal models suggest that a dysbalance between serotonin, glutamate, and dopamine in t...
To date, there is no doubt that dopamine plays a key role in the behavioural disorders associated with schizophrenia. However, dopamine is not the only neurotransmitter involved in this syndrome, as it interacts with many neuronal systems in brain. Of special interest is the interaction between dopaminergic and serotoninergic systems with evidence from pharm...
Hallucinogenic drugs are unique in that they produce the desired hallucinogenic effects at what are considered non-toxic doses. The hallucinogenic drugs can be categorised into 4 basic groups: indole alkaloid derivatives, piperidine derivatives, phenylethylamines and the cannabinols. The drugs reviewed include lysergic acid diethylamide (LSD), phencyclidine ...
Three hallucinogens (d-lysergicacid diethylamide (LSD), mescaline, psilocybin) and two cannabinoid derivatives (tetrahydrocannabinol (THC), synhexyl) were tested for their long-term effects on the EEG of the cat. The drug-induced alterations in the EEG frequency spectrum were "drug-specific" in the sense that they would be statistically unlikely to occur dur...
The classical conditioning potential of several drugs was tested in rats by pairing a light CS with the drug UCSs; these stimuli were superimposed in a variable-interval 30 sec schedule for water reinforcement. Conditioning (suppression of bar-pressing in the presence of the CS) was definitely demonstrated with psilocybin (2.0 mg/kg), was suggested but not c...
Evidence has been presented that d-amphetamine interacts with various types of behavior in the context of a conditioning paradigm. Rats exposed simultaneously to a locomotor activity measurement and three dose levels of d-amphetamine on repeated occasions gradually developed dose-related enhancement of drug-stimulated activity, which persisted after disconti...
Using apparent fronto-parallel plane (AFP) monitoring techniques, the relative stability of the abathic plane, i.e., Euclidean visual space, was investigated in 16 volunteers with a median age of 23.5 years under 160 µg/kg psilocybin-induced ergotropic arousal. Handwriting area and pressure were also measured in the same subjects. Drug-induced contraction of...
Autonomic, perceptual, and behavioral changes induced by 160 µg/kg psilocybin were studied in a homogenous sample of 15 self-selected College educated male and female volunteers. The subjects were rank ordered as to the extent of drug-induced psychopathology using their Minnesota Multiphasic Personality Inventory pre-drug to drug peak differences scores. Ext...
