PLoS One
November 4, 2013
Alvaro Llorente‐berzal, Emma Puighermanal, Aurelijus Burokas et al.
43 citations
Adolescent rats given THC (the main psychoactive component of cannabis) and/or MDMA (ecstasy) showed lasting, sex-dependent changes in behavior and brain chemistry. MDMA reduced exploration and increased anxiety-like behavior shortly after treatment. Long-term, THC disrupted object recognition memory in females but not males. MDMA alone weakened prepulse inhibition (a measure of sensorimotor gating) at the loudest sound tested, while combining it with THC caused a similar deficit at a softer sound. In the brain, THC reduced Arc protein in the hippocampus of both sexes but in the frontal cortex only in females.
PLoS One
May 13, 2016
Ellen M. Lee, Kathryn R. Klement, James K. Ambler et al.
42 citations
An extreme ritual involving temporary body piercings and dancing induced altered states of consciousness in both pierced dancers and non-pierced participants, as measured by tests of transient hypofrontality and flow. Both groups reported decreases in negative affect and psychological stress and increases in intimacy from before to after the ritual. However, physiological responses differed: pierced dancers showed increases in the stress hormone cortisol, while non-pierced participants showed decreases during the ritual. The ritual produced similar psychological effects but different physiological effects across participant roles.
PLoS One
July 23, 2020
Joshua M. Martin, Danyal Wainstein Andriano, Natália Bezerra Mota et al.
41 citations
Dream reports collected after rapid eye movement (REM) sleep are typically longer, more vivid, and more story-like than those from non-REM sleep, but traditional measures may be confounded by report length. By analyzing 133 dream reports from 20 participants as non-semantic directed word graphs, researchers found that REM dream reports have greater connectedness—words recur with longer range—compared to N2 sleep reports. Graph measures predicted dream complexity, with higher connectedness and lower randomness linked to more complex reports. The largest connected component improved models using report length alone for predicting sleep stage and complexity. Graph analysis offers an automated method to complement traditional dream report analysis.
PLoS One
May 6, 2015
Elena Antonova, Paul Chadwick, Veena Kumari
41 citations
Intensive mindfulness practice attenuates habituation of the acoustic startle reflex, meaning experienced meditators continue to respond strongly to repeated startling sounds rather than tuning them out. Moderate practice, however, enhances habituation, suggesting a non-linear effect of practice intensity. The study measured eye-blink muscle responses to 36 loud noises in three groups: meditation-naïve, moderate practice, and intensive practice. Only the intensive practice group showed reduced habituation across the entire experiment. Greater practice intensity correlated with slower habituation in the intensive group. The effect is modest and provides tentative evidence that intensive mindfulness may alter automatic sensory processing.
PLoS One
December 31, 2014
I-Hsun Li, Kuo-Hsing Ma, Shao-Ju Weng et al.
40 citations
Autophagy activation contributes to the neurotoxicity caused by 3,4-methylenedioxymethamphetamine (MDMA, or 'ecstasy') in cultured cortical neurons.
PLoS One
January 1, 2023
Edie L Sperling, Jennifer M Hulett, Leeanne B Sherwin et al.
38 citations
Mindfulness interventions reduce stress in medical students by a small-to-moderate amount. A systematic review and meta-analysis of 35 studies found that these interventions significantly improved stress levels in both two-arm studies (effect size 0.37) and one-arm pre-post studies (effect size 0.29). Trends from moderator analyses suggested that fewer hours and less required practice led to better stress improvement. The findings confirm that a wide variety of mindfulness programs worldwide produce consistent stress reduction in this high-stress population.
PLoS One
April 13, 2019
Patrick Vizeli, Matthias E. Liechti
37 citations
MDMA increases oxytocin, empathy, and prosociality. In a pooled analysis of eight double-blind, placebo-controlled studies involving up to 132 healthy subjects, a specific genetic variant of the oxytocin receptor (rs1042778 TT genotype) was linked to greater feelings of trust after MDMA compared to G allele carriers, but only in a subset of 53 subjects. Other variants (rs53576 and rs2254298) did not moderate MDMA's subjective effects. MDMA increased plasma oxytocin concentrations, but oxytocin levels did not differ by gene variant. The results suggest oxytocin receptor variations may influence some prosocial effects of MDMA, but interpretation is cautious due to small sample sizes.
PLoS One
January 1, 2024
Xiaohui Wang, Zhicheng Dai, Xinying Zhu et al.
36 citations
A systematic review and meta-analysis of 11 randomized controlled trials involving 1644 breast cancer patients found that mindfulness-based stress reduction therapy, compared with standard care, significantly reduces negative emotions including perceived stress, depression, anxiety, and fear of recurrence. The therapy also improves patients' coping ability and emotional state. These findings support the use of mindfulness-based stress reduction to enhance quality of life in breast cancer patients by alleviating psychological distress.
PLoS One
January 1, 2013
Tamara Antonio, Steven R Childers, Richard B Rothman et al.
36 citations
Iboga alkaloids, including ibogaine, its metabolite noribogaine, and the synthetic compound 18-methoxycoronaridine (18-MC), were tested for their ability to activate the μ-opioid receptor (MOR), a common target of opioid drugs. In rat thalamic membranes, all three compounds acted as antagonists, blocking the receptor rather than activating it, with functional Ke values ranging from 3 μM for ibogaine to 13 μM for noribogaine and 18-MC. None of the compounds stimulated MOR-related G protein activity in cells expressing human or rat MORs, and only limited partial agonist effects were seen in mouse MOR-expressing cells. The findings indicate that an opioid agonist mechanism does not explain these alkaloids' effects on opioid withdrawal, supporting a novel mechanism of action and justifying further search for alternative targets.
PLoS One
April 9, 2013
Oliver G. Bosch, Michael Wagner, Frank Jessen et al.
34 citations
Recreational users of MDMA show verbal learning and recall deficits that are linked to reduced glucose metabolism in the prefrontal and parietal cortex, and word recognition difficulties are additionally associated with reduced metabolism in the mediotemporal region. These findings indicate that memory problems in MDMA users result from combined dysfunction across frontal, parietal, and mediotemporal brain areas.
PLoS One
December 12, 2018
M. Hirshberg, Simon B. Goldberg, S. Schaefer et al.
33 citations
Different styles of brief contemplative practices produce distinct effects on affect and behavior, especially under stress. In a randomized experiment with 156 undergraduates, gratitude training improved positive affect more than breath awareness, while loving-kindness reduced implicit negative affect more than a control condition. However, gratitude training also increased reactivity to a cold pressor stressor: participants reported it as more aversive and showed greater increases in negative affect. Those with greater gains in implicit positive affect after gratitude training later rated neutral faces as less likable and were less likely to donate time to help others. These findings suggest that even brief introductory practices can have divergent outcomes, which may be amplified by stress.
PLoS One
December 30, 2015
Vanessa Manchim Favaro, Maurı́cio Yonamine, Juliana Carlota Kramer Soares et al.
33 citations
Long-term daily administration of ayahuasca to rats for 30 days did not affect their performance in the Morris water maze or elevated plus maze tasks. However, a dose of 120 mg/kg increased the contextual conditioned fear response for both background and foreground fear conditioning, while the tone-conditioned response remained unaffected. This heightened contextual fear response persisted across repeated sessions several weeks after training. These results indicate that long-term ayahuasca exposure can selectively enhance the contextual association of emotional events, consistent with the beverage's known activation of brain regions involved in emotional processing and memory.
PLoS One
July 7, 2014
Bruno Gingras, Gerald Pohler, W. Tecumseh Fitch
33 citations
Repetitive drumming paired with shamanic instructions produces distinct subjective experiences, such as visions or altered states, but does not lead to a greater reduction in cortisol levels compared to listening to instrumental meditation music. The findings suggest that while the shamanic practice can evoke specific psychological effects, its physiological stress-reducing impact is not superior to that of meditation music.
PLoS One
September 10, 2013
Niklaus Denier, Hana Gerber, Marc Vogel et al.
32 citations
In 15 heroin-dependent patients receiving stable heroin-assisted treatment, heroin reduced blood flow in the left anterior cingulate cortex, left medial prefrontal cortex, and insula compared to placebo. These brain areas are involved in self-regulation and emotional processing. The findings suggest that heroin's effects on these regions may contribute to its ability to reduce craving and produce relaxation in maintenance therapy.
PLoS One
January 1, 2023
Ahmed M Alzahrani, Ahmed Hakami, Ahmad Alhadi et al.
31 citations
An eight-week Mindfulness-based Stress Reduction (MBSR) program delivered via audiovisual materials to medical students in Saudi Arabia did not show immediate differences between the MBSR and waitlist groups at post-program, but at three-month follow-up the MBSR group had a significant drop in anxiety. Attending more MBSR sessions was linked to lower depression and anxiety. Males in the MBSR group improved in stress, anxiety, and mindfulness; females improved only in stress. The study was interrupted by the COVID-19 outbreak, but the findings suggest that MBSR can improve psychological outcomes when participants commit to the program.
PLoS One
December 18, 2012
Stanley C. Flavel, Jenna D. Koch, Jason M. White et al.
30 citations
Abstinent ecstasy users show abnormally large tremor during movement compared to non-drug users, while resting tremor remains unaffected. The study measured tremor with an accelerometer in abstinent ecstasy users (n=9), users of amphetamine-like drugs (n=7), cannabis users (n=12), and non-drug users (n=23). During finger movement, tremor amplitude was significantly greater in ecstasy users (frequency range 3.9-13.3 Hz) but not in cannabis or amphetamine users. Peak tremor frequency did not differ between groups. The finding suggests chronic ecstasy use may produce lasting motor effects, though further research is needed to determine if this increases risk of movement disorders.
PLoS One
December 14, 2022
Meghan DellaCrosse, Mollie Pleet, Emma Morton et al.
28 citations
Adults with bipolar disorder who used psilocybin-containing mushrooms reported both benefits and risks. Benefits included reduced depression severity, improved emotion processing, new perspectives, and better relaxation and sleep. Risks included changes in sleep, increased mania severity, hospitalization, and distressing sensory experiences. Contextual factors such as poly-substance use, psilocybin dose, solo versus social use, and pre-use sleep deprivation influenced outcomes. The findings highlight the need for carefully designed clinical trials to assess safety and preliminary efficacy of psilocybin therapy in this population.
PLoS One
January 1, 2025
Eirini K. Argyri, Jules Evans, David Luke et al.
27 citations
Psychedelic experiences can sometimes trigger long-lasting existential distress, marked by confusion about existence and purpose, alongside cognitive, emotional, social, and bodily difficulties. Interviews with 26 people who experienced such distress revealed that ontological challenges—struggles with understanding reality—were common. Participants alleviated distress primarily through 'grounding' practices: embodiment, social connection, and cognitive normalization of their experience. The findings suggest psychedelic experiences act as pivotal mental states that can facilitate transformative learning, challenging and expanding meaning-making. This work contributes to understanding how people reestablish coherence and grow after ontologically challenging psychedelic experiences.
PLoS One
January 2, 2024
Caroline Peacock, Erin Brauer, Ali John Zarrabi et al.
27 citations
Spiritual health practitioners bring unique expertise to psychedelic-assisted therapy based on their training and professional experience. Interviews with 15 such practitioners revealed seven themes in two domains: unique contributions (competency with spiritual material, awareness of power dynamics, familiarity with non-ordinary states, holding space, counterbalancing biomedical perspectives) and general contributions (using general therapeutic skills and supporting interdisciplinary collaboration). Their skills complement other clinical team members, and psychedelic-assisted therapy teams may benefit from including them. Further work is needed to define roles, qualifications, and training for these clinicians.
PLoS One
October 6, 2021
Claudia Picard-Deland, Tore Nielsen, Michelle Carr
27 citations
Over a third of dreams collected in a sleep laboratory incorporate elements of the lab itself, such as experimenters, electrodes, or the setting. These lab incorporations are especially common during REM sleep (44.2%) and morning naps (48.4%). They tend to be associated with higher depression scores but not with sex, nightmare-proneness, or anxiety. Common themes include meta-dreaming (lucid dreams and false awakenings, 40.7%), sensory incorporations (27%), wayfinding (24.3%), sleep as performance (19.6%), friends or family in the lab (15.9%), and being an object of observation (12.2%). Nearly a third of these dreams projected the dreamer into the near future, while very few projected into the past.
PLoS One
November 25, 2020
Gerlinde C. Harb, Jon‐Håkon Schultz
27 citations
Adolescents in the Gaza Strip who have lived through three wars and ongoing conflict report, on average, five nightmares per week for three years, with disrupted sleep, fear of going to sleep, and not feeling rested in the morning. Nearly 60% of nightmares include the threat of death, and many contain surreal elements alongside realistic violence. Both students and teachers report impaired academic functioning and daytime sleepiness. Nightmare symptoms are associated with school functioning impairment. The authors suggest that increasing self-efficacy in relation to recurrent nightmares may be a useful intervention point for these traumatized youth.
PLoS One
January 1, 2021
Shih-Han Hung, Ching-Yung Hwang, Chun-Yen Chang
23 citations
A quantitative and qualitative analysis of the relationship between the Qi experience and the flow experience found a high level of consistency between the two concepts (correlation coefficient r = 0.90). The Qi experience, described as a healthy energy gained from the environment and an inner feeling, was integrated into five orientations: the feeling of Qi; the mind; Qi and consciousness; physical, mental, and spiritual benefits; and the feeling of Tao. The results suggest that the flow experience in Qigong activity is the same as the Qi experience in East Asian disciplines.
PLoS One
December 28, 2020
Sergio Hernández, Roberto Dorta‐Guerra, José Suero et al.
23 citations
Long-term practitioners of Sahaja Yoga Meditation had larger grey matter volume overall compared to non-meditators, with significant differences in the right temporal and frontal lobes, left frontal lobe, and brainstem. The differences were more pronounced in right hemisphere brain areas, suggesting neuroplastic changes linked to emotional and attentional control developed through meditation. The study used a novel statistical approach that identified more brain regions with significant volume differences than traditional methods, which may be prone to Type II errors.
PLoS One
February 23, 2016
Kim P. C. Kuypers, Eef L. Theunissen, Janelle H. P. van Wel et al.
23 citations
Verbal memory performance in people who use Ecstasy (MDMA) does not differ from that of healthy non-users when they are not under the drug's influence, and there is substantial evidence supporting no long-term memory deficit. Clinically significant memory impairment—defined as performance more than 1.5 standard deviations below the average of healthy controls—was absent during abstinence. However, during acute MDMA intoxication, verbal memory was impaired. Pooled data from four experimental studies compared 65 Ecstasy users tested on placebo with 65 matched drug-naïve controls. History of use did not predict memory impairment. The findings suggest that Ecstasy/MDMA use does not cause clinically deficient long-term verbal memory.
PLoS One
March 22, 2022
Erin J. Wamsley
22 citations
The constructive episodic simulation hypothesis, which proposes that waking thought combines fragments of past episodes to imagine future events, may also explain dreaming. In a study of 48 college students who identified waking-life sources for 469 dreams, 53.5% of dreams were traced to at least one past episodic source and 25.7% to a future episodic source. 43.9% of dreams with content drew on multiple waking sources, incorporating memory fragments into scenarios anticipating future events. The phenomenology and distribution of dream sources across time and sleep stage provide evidence that dreams use memory to simulate potential futures, not merely reflect the past.