Social Neuroscience
June 25, 2009
Glenn Dumont, Fred C.g.j. Sweep, R. van der Steen et al.
238 citations
MDMA (ecstasy) causes a strong increase in blood oxytocin levels and enhances feelings of prosociality in healthy people. The changes in prosocial feelings are more closely tied to changes in oxytocin than to changes in MDMA concentration in the blood. This suggests that oxytocin release may be a key mechanism behind the drug's characteristic social effects.
Anesthesiology
August 13, 2012
Marieke Niesters, Najmeh Khalili‐mahani, Christian H. Martini et al.
141 citations
Low-dose S(+)-ketamine alters the brain's intrinsic large-scale functional connectivity, as measured by resting-state fMRI. In twelve healthy men, ketamine increased connectivity in the cerebellum and visual cortex while decreasing connectivity in auditory and somatosensory networks, including regions involved in pain sensing and affective processing such as the amygdala, insula, and anterior cingulate cortex. Pain-related connectivity changes occurred in areas responsible for descending pain inhibition, including the anterior cingulate cortex, insula, orbitofrontal cortex, and brainstem. These connectivity changes correspond to ketamine's known effects on analgesia, psychedelic experiences, and other side effects.
Psychopharmacology
February 1, 2018
Randall L. Morrison, Maggie Fedgchin, Jaskaran Singh et al.
72 citations
Intranasal esketamine temporarily impairs cognitive performance and increases mental effort and sleepiness in healthy participants. At 40 minutes after dosing, performance on five cognitive tests (Detection, Identification, One-Card Learning, One Back, and Groton Maze Learning) was significantly worse compared with placebo. These effects resolved by 2 hours postdose, with no differences between esketamine and placebo at 2, 4, or 6 hours. Participants reported greater mental effort at 40 minutes and increased sleepiness at 40 minutes and 2 hours, which also returned to placebo levels later. Common mild adverse events included dizziness, nausea, attention disturbance, and fatigue.
Psychopharmacology
February 28, 2008
Glenn Dumont, E. Wezenberg, M. M. G. J. Valkenberg et al.
50 citations
Taking MDMA and ethanol together does not worsen the effects of either drug alone. While the impairment caused by each drug condition was relatively moderate, all drug conditions significantly impaired cognitive function.
Clinical and Translational Science
May 1, 2025
Katelijne V. van der Heijden, Rob G J A Zuiker, Marije E. Otto et al.
7 citations
Intravenous DMT administered as a 30-second bolus followed by a 6-hour infusion, reaching peak blood concentrations around 35 ng/mL, is safe in healthy volunteers. No serious adverse events occurred; all side effects were mild and self-limiting. Vital signs, electrocardiography, and measures of suicidality or psychopathology showed no significant abnormalities. Mild psychedelic effects were accompanied by temporary decreases in sustained attention, postural stability, and occipital alpha brain wave power at the highest dose. Moderate variability in drug levels between individuals was observed. These findings support further testing of prolonged DMT infusion as a potential treatment to promote neuroplasticity in stroke recovery.
Frontiers in Neuroscience
January 1, 2025
Kasper Recourt, Joop van Gerven, Nadieh Drenth et al.
1 citation
Ketamine, given intravenously at 0.5 mg/kg, rapidly reduces depression symptoms in patients with non-treatment-resistant major depressive disorder. In a randomized, double-blind, placebo-controlled crossover study with 16 patients, ketamine lowered mean MADRS scores from 21.2 before dosing to 10.3 at 24 hours, compared with placebo. Resting-state fMRI showed that ketamine altered functional connectivity only in brain circuits previously linked to depression—the corticolimbic-insular-striatal-pallidal-thalamic (CLIPST) network—at both acute (50–165 minutes) and delayed (24 hours) time points. No connectivity changes occurred outside this depression-related circuitry. The results indicate that ketamine specifically targets depression-associated neural pathways, supporting model-based analysis in future pharmaco-fMRI studies.
Journal of psychopharmacology (Oxford, England)
June 25, 2026
Joost C Van Mechelen, Tobias A Wieles, Laura Borghans et al.
Oral S-ketamine (S-KETPO) has poor bioavailability (9-12%) and produces much lower peak concentrations of S-ketamine but higher levels of its active metabolites norketamine and hydroxynorketamine compared to intravenous S-ketamine (S-KETIV). In 16 healthy participants, S-KETIV caused sedative, psychomotor, and psychotomimetic effects along with reductions in brain electrical activity, while the higher oral dose (0.45 mg/kg) showed limited psychotomimetic effects and smaller brain activity reductions, and the lower oral dose (0.20 mg/kg) had no effects. Safety was similar across treatments. These pharmacokinetic and pharmacodynamic differences may affect dose selection and therapeutic outcomes in treatment-resistant depression.