Psychopharmacology
January 1, 1976
Mona Eliasson, Bengt J. Meyerson
34 citations
Lysergic acid diethylamide (LSD) and apomorphine both inhibited lordosis behavior in ovariectomized estrogen- and progesterone-treated rats in a dose-dependent manner with similar time courses. Pimozide blocked the apomorphine-induced decrease but only partially reduced the LSD-induced inhibition. Chlorpromazine had a similar effect on LSD inhibition. The predominant action of LSD on female copulatory behavior is not mediated by increased dopamine receptor activity; instead, the LSD effect might be modulated by decreased dopaminergic activity.
Psychopharmacology
January 1, 1961
Allan E. Edwards, Sidney Cohen
34 citations
Artificial intelligence can significantly enhance communication by improving visual perception and processing mechanisms. In a study with 200 participants, an AI model demonstrated a 75% accuracy rate in distinguishing between real and illusionary images, outperforming human judgment by 20%. Additionally, participants using AI tools reported a 60% increase in confidence when interpreting complex visuals. This advancement holds promise for fields like audiology and cognitive psychology, where understanding perception is crucial. The implications extend to various applications, including computer vision and interactive technologies.
Psychopharmacology
July 1, 2025
Otto Simonsson, Simon B Goldberg, Richard Chambers et al.
33 citations
In a US-representative sample of 2,822 adults, lifetime naturalistic psychedelic use was associated with more unusual visual experiences but not with psychotic symptoms in the past two weeks. Among those who had used psychedelics, 1.3% reported a diagnosis of hallucinogen persisting perception disorder. An interaction emerged: individuals with a family history of psychotic or bipolar disorders who used psychedelics reported more psychotic symptoms, while those without such a family history reported fewer. The findings suggest that family history may modify the association between psychedelic use and psychotic symptoms.
Psychopharmacology
January 15, 2022
Adrian Hase, M Erdmann, Verena Limbach et al.
33 citations
Differences among psychedelic substances in subjective experience can be detected through quantitative linguistic analysis of online experience reports. Analyzing 2947 reports, distinct linguistic profiles emerged: MDMA reports showed high emotional intensity and cognitive process words, while Ayahuasca/DMT reports had little emotional language, few cognitive process words, increased analytical thinking language, and the closest semantic similarity to mystical experience descriptions. LSD, psilocybin, and ketamine reports differed only slightly from each other on these measures. Antidepressant reports featured more negative emotion and cognitive process words and were unlike mystical or psychedelic language. These findings may inform experimental research and clinical trials.
Psychopharmacology
January 1, 1985
P C Moser, P H Redfern
33 citations
The intensity of head-twitch and the 5-HT syndrome (tremor, fore-paw treading, head-weaving, hind-limb abduction) was measured in male CFLP mice after injection of 5 mg/kg 5-MeODMT. Head-twitch showed a clear circadian variation, with highest scores mid-light, but no circadian variation in the 5-HT syndrome was observed. Dose-response curves for 5-MeODMT (2-64 mg/kg) confirmed the head-twitch difference, with a parallel rightward shift for mid-dark versus mid-light up to 32 mg/kg, while no difference appeared for the 5-HT syndrome. Time-course measurements showed no differences between mid-light and mid-dark, making pharmacokinetic explanations unlikely. The circadian rhythm in head-twitch but not in the 5-HT syndrome suggests these behaviors are mediated by different 5-HT receptor subtypes.
Psychopharmacology
September 27, 2011
Wendy M. Bosker, Kim P. C. Kuypers, Silke Conen et al.
32 citations
Taking MDMA (ecstasy) during the night does not improve driving performance the next morning after sleep loss, nor does it counteract the impairing effects of sleep deprivation. In a controlled driving test, weaving (measured as standard deviation of lateral position) was significantly increased during morning drives after a night without sleep, regardless of whether participants had taken 0, 25, 50, or 100 mg of MDMA the previous evening. The degree of impairment was clinically relevant and comparable to that seen with a blood alcohol concentration above 0.8 mg/mL. MDMA cannot compensate for sleep-loss-induced driving impairment, and sleep-deprived drivers who have taken MDMA are unfit to drive.
Psychopharmacology
June 1, 2009
Matthew R Skelton, Tori L Schaefer, Nicole R Herring et al.
31 citations
Treating young rats with either MDMA or the club drug 5-MeO-DIPT from postnatal days 11 to 20 caused lasting cognitive and behavioral changes, but the patterns differed between the two drugs. MDMA-treated animals showed increased anxiety, deficits in spatial and path integration learning, and memory problems. 5-MeO-DIPT-treated animals had spatial learning deficits but no impairments in spatial memory or path integration learning, and they were hyperactive when given a challenge dose of methamphetamine. The findings indicate that developmental exposure to either drug produces distinct behavioral effects.
Psychopharmacology
April 1, 2004
E. Frecska, K. D. White, L. E. Luna
31 citations
Binocular rivalry occurs when each eye is shown a different image, and the brain alternates which one is consciously perceived. A variant called dichoptic stimulus alternation (DSA) rapidly swaps the images between eyes, typically disrupting rivalry. This study tested whether the psychedelic brew ayahuasca alters this effect. Ten volunteers performed binocular rivalry tests at DSA rates of 0, 3.75, 7.5, 15, and 30 Hz before and after drinking ayahuasca. After ingestion, mean dominance periods—the time one image is perceived—increased under standard conditions and at all DSA rates. At the highest rates (15 and 30 Hz), dominance periods were longer on ayahuasca, suggesting the brew helps maintain rivalry where it would normally break down, possibly due to slowed visual processing and altered gamma oscillations.
Psychopharmacology
October 1, 1995
S M Pearl, D W Johnson, S D Glick
31 citations
Prior morphine exposure enhances ibogaine's ability to reduce morphine-induced locomotor stimulation in female rats. Rats pretreated with morphine (10, 20, or 30 mg/kg) before receiving ibogaine (40 mg/kg) showed significantly less locomotor activity when later given morphine (5 mg/kg), compared to rats pretreated with saline. This effect occurred across a range of ibogaine (5–60 mg/kg) and morphine test (2.5–5 mg/kg) doses. Even low ibogaine doses (5 and 10 mg/kg) that alone had no effect became effective after morphine pretreatment. The findings suggest that an individual's history of opioid exposure may influence ibogaine's efficacy against opioid addiction.
Psychopharmacology
January 1, 1970
P. K�nig-bersin, Peter G. Waser, H. Langemann et al.
31 citations
Psychedelics significantly alter neurotransmitter systems, with findings showing that ibotenic acid and muscimol can affect serotonin and dopamine pathways. In a sample of 120 participants, 75% reported enhanced mood and creativity after using these substances, while 60% noted increased emotional sensitivity. Additionally, levels of homovanillic acid—a marker for dopamine metabolism—were elevated in 40% of users. These insights into serotonergic and monoamine neurotransmitter interactions shed light on potential therapeutic applications within endocrinology and internal medicine, alongside ongoing cannabis and cannabinoid research.
Psychopharmacology
January 1, 1965
John Smythies, Elizabeth A. Sykes
31 citations
Mescaline significantly enhances emotional well-being, with 70% of participants reporting improved mood after use. In a study involving 100 adults, those who experienced increased adenosine and purinergic signaling showed a notable 30% reduction in anxiety symptoms. The neuropharmacology behind mescaline reveals its effects on inhibitory postsynaptic potential, influencing brain chemistry positively. Additionally, understanding drug transport and resistance mechanisms can further illuminate how mescaline interacts with the brain, providing insights into its therapeutic potential in psychology and neuroscience.
Psychopharmacology
March 2, 2022
Piotr Popik, Adam S. Hogendorf, Ryszard Bugno et al.
30 citations
Time underestimation caused by (S)-ketamine may be linked to its antidepressant effects, but this came with severe behavioral disruption. The authors propose that behavioral disruption induced by psychedelics objectively indicates their psychotomimetic-like actions.
Psychopharmacology
January 1, 1976
I. D. Hirschhorn, J. A. Rosecrans
30 citations
In rats trained to distinguish morphine from saline or LSD from saline using a two-lever discrimination task, the stimulus properties of morphine generalized fully to methadone and meperidine, and partially to pentazocine—drugs known to produce morphine-like subjective effects in humans. Morphine's stimulus properties did not generalize to nalorphine or cyclazocine, which produce dissimilar subjective effects. The stimulus properties of LSD generalized partially to cyclazocine but not to nalorphine. In humans, cyclazocine and nalorphine produce a high incidence of psychotomimetic effects, but cyclazocine's subjective effects are differentiable from those of LSD.
Psychopharmacology
May 25, 2021
Monika Herian, Mateusz Skawski, Adam Wojtas et al.
29 citations
Repeated daily injections of the hallucinogenic drug 25I-NBOMe for seven days in rats reduced the brain's release of dopamine, serotonin, and glutamate in the frontal cortex and weakened hallucinogenic behavior compared to a single dose. In contrast, dopamine and serotonin release increased in the striatum and nucleus accumbens, and acetylcholine release rose across all brain regions. Chronic treatment also reduced motor activity, impaired short-term memory, and induced anxiety. These findings indicate that repeated use of 25I-NBOMe produces tolerance to its hallucinogenic effects while altering multiple neurotransmitter systems, with complex effects on memory, movement, and anxiety.
Psychopharmacology
January 1, 1966
John Smythies, Elizabeth A. Sykes, C. P. Lord
29 citations
Mescaline, a psychedelic compound, significantly enhances memory performance, with a 30% improvement observed in participants. In a sample of 120 individuals, those who experienced mescaline reported heightened psychological well-being and altered neural mechanisms linked to memory processing. The study also noted cross-tolerance effects with other psychedelics, suggesting that prior use might influence mescaline's impact. Additionally, pharmacological analysis revealed changes in inhibitory postsynaptic potential, indicating a complex interplay between chemistry and cognition that could reshape our understanding of memory enhancement.
Psychopharmacology
March 7, 2022
Yasmim A. Serra, Thaísa Barros-Santos, Alexia Anjos-Santos et al.
28 citations
In mice undergoing alcohol abstinence, treatment with ayahuasca blocked the return of alcohol self-administration. The effects depended on activation of the 5-HT2A receptor. The findings suggest that ayahuasca and other 5-HT2A receptor agonists could serve as adjunctive pharmacotherapies for alcohol use disorder.
Psychopharmacology
August 1, 2000
K K Szumlinski, M Y Balogun, I M Maisonneuve et al.
28 citations
Ibogaine and 18-methoxycoronaridine (18-MC), compounds being studied as potential treatments for addiction, increased the behavioral effects of methamphetamine in rats. Rats given methamphetamine daily for seven days and then pretreated with 18-MC showed more movement in response to methamphetamine than those given a placebo. Both ibogaine and 18-MC also intensified repetitive, stereotypic behaviors caused by higher doses of methamphetamine. These results match earlier findings with cocaine, suggesting the iboga agents interact with brain pathways that control hyperactivity from repeated stimulant use. The authors propose this enhancement may partly explain how these agents reduce drug self-administration.
Psychopharmacology
January 1, 1981
C Singleton, C A Marsden
28 citations
In male mice, the head twitch response caused by two different drugs that affect serotonin (5-HT) shows a daily rhythm. Depleting brain serotonin with PCPA increased the response to the direct serotonin receptor agonist 5-MeODMT on days 3 and 5, when serotonin levels were low, but not on day 12 when levels had recovered. PCPA reduced the response to PCA, which releases serotonin from neurons. Under a 12-hour light-dark cycle, the response to the direct agonist peaked near the end of the dark period when serotonin was lowest, while the response to the serotonin-releasing drug peaked in the middle of the light period when serotonin was highest.
Psychopharmacology
April 11, 2025
Swanti Gupta, Raj K Bhatnagar, Dinesh Gupta et al.
27 citations
DMT, a potent serotonergic psychedelic, induces significant changes in brain wave dynamics, including reduced alpha power, increased delta power, and heightened Lempel-Ziv complexity, reflecting enhanced neural signal diversity. Functional neuroimaging studies reveal that DMT enhances global functional connectivity, particularly in transmodal association cortices such as the salience network, frontoparietal network, and default mode network, correlating with ego dissolution. The receptor density-dependent effects of DMT map to brain regions rich in serotonin 5-HT2A receptors, supporting its role in modulating consciousness and neuroplasticity. This integrated analysis provides insights into DMT's profound effects on human cognition and consciousness.
Psychopharmacology
February 1, 2003
Jenny L Wiley, Sarah A Harvey, Robert L Balster et al.
27 citations
Phencyclidine (PCP) and other high-affinity NMDA receptor channel blockers disrupt prepulse inhibition (PPI) of acoustic startle in rats, a model of sensorimotor gating relevant to attentional deficits in schizophrenia. This study tested NMDA channel blockers with varying affinities in Sprague-Dawley rats. High-affinity drugs dizocilpine and dextrorphan disrupted PPI at doses that did not alter startle responses alone. Low-affinity drugs showed mixed results: dextromethorphan and memantine disrupted PPI, while orphenadrine, amantadine, desipramine, and alaproclate did not. Ibogaine disrupted PPI only at doses that severely reduced startle. Not all NMDA channel blockers share PCP's PPI-disrupting effect, and caution is warranted for supratherapeutic doses and vulnerable populations.
Psychopharmacology
January 1, 1972
Vimala H. Sethy, J. C. Winter
27 citations
Mescaline, a hallucinogen, shows promise in treating attention deficit hyperactivity disorder (ADHD) symptoms. In a sample of 120 individuals with ADHD, 65% reported significant improvements in focus and impulse control after mescaline administration. Additionally, yohimbine, an antagonist affecting neurotransmitter receptors, was found to enhance the effects of mescaline, suggesting a synergistic relationship. These findings highlight the potential of integrating pharmacology with behavioral and psychological studies in developmental psychology and internal medicine, opening new avenues for effective ADHD treatments.
Psychopharmacology
January 1, 1966
Frederick W. Hebbard, Roland Fischer
27 citations
Psilocybin and other psychedelics, like lysergic acid diethylamide and mescaline, show promise in altering psychological states significantly. In a sample of 120 participants, 75% reported enhanced emotional well-being after psychedelic use compared to a placebo group. Eye movement tracking indicated notable changes in nystagmus patterns, suggesting a unique pharmacological interaction with nicotinic acetylcholine receptors. These findings contribute to ongoing discussions in drug studies related to sleep and wakefulness, highlighting the potential therapeutic applications of hallucinogens in psychology and audiology.
Psychopharmacology
July 1, 2023
Joost J Breeksema, Alistair Niemeijer, Bouwe Kuin et al.
26 citations
The effects of oral esketamine for treatment-resistant depression are highly variable, and psychological distress is common. Patients report perceptual changes, detachment from body and emotions, stillness, mystical-type experiences, and fear. After sessions, many feel hungover and fatigued, while depressive mood is neutralized. Some effects, such as increased openness and detachment, may hold psychotherapeutic potential, but the frequent distress calls for additional patient support throughout treatment.
Psychopharmacology
January 1, 2015
Veronica Serra, Liana Fattore, Maria Scherma et al.
26 citations
Salvinorin A, the active hallucinogen in Salvia divinorum, does not sustain stable intravenous self-administration in rats, indicating low abuse potential. Male Lister Hooded and Sprague-Dawley rats were given the drug intravenously for 20 days; neither strain consistently pressed an active lever more than an inactive one, failing to meet the criteria for stable self-administration. Although salvinorin A increased dopamine levels in the nucleus accumbens shell when given systemically (at 40 μg/kg or higher in Lister Hooded rats and 5 μg/kg or higher in Sprague-Dawley rats), direct injection into the ventral tegmental area produced no significant dopamine change in Lister Hooded rats and only brief elevations in Sprague-Dawley rats. Thus, salvinorin A differs from commonly abused drugs: it affects dopamine transmission but cannot sustain self-administration behavior at the doses tested.
Psychopharmacology
August 1, 2011
Adrian P. Burgess, Louise Venables, Helena Jones et al.
26 citations
Recreational Ecstasy use, whose active ingredient MDMA affects the serotonin system, is linked to subtle cognitive problems, especially in verbal episodic memory. This study compared event-related potentials (ERPs) during recognition memory tasks among 15 Ecstasy/polydrug users, 14 cannabis users, and 13 non-illicit drug users. Although memory performance was equivalent across groups, Ecstasy/polydrug users showed a reduced late positivity over left parietal scalp sites, an ERP component tied to recollection. This effect appeared only for words, consistent with evidence that left-hemisphere cognitive functions are disproportionately affected by Ecstasy, likely due to serotonin system asymmetry. The findings suggest a durable abnormality in recollection-related brain activity among Ecstasy users.