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Rj Verkes

3 papers in the library · 98 citations · publishing 2009-2015

Papers

Acute psychomotor, memory and subjective effects of MDMA and THC co-administration over time in healthy volunteers

Journal of Psychopharmacology September 3, 2010 Gjh Dumont, J. G. Coen van Hasselt, M. de Kam et al. 38 citations

Combining MDMA and THC does not worsen cognitive impairment beyond that caused by THC alone, but it does increase the desired subjective drug effects and perceived drug strength, which may explain why many young people use them together. In a placebo-controlled crossover trial with 16 healthy volunteers aged 18–27, THC alone produced more robust cognitive impairment than MDMA alone, and co-administration did not exacerbate single-drug effects on cognitive function. However, the combination enhanced subjective experiences compared with MDMA alone.

Acute psychomotor effects of MDMA and ethanol (co-) administration over time in healthy volunteers

Journal of Psychopharmacology January 22, 2009 Gjh Dumont, Rik C. Schoemaker, Daan J. Touw et al. 37 citations

Combining MDMA (ecstasy) with alcohol impairs psychomotor accuracy even though it increases feelings of arousal and psychomotor speed. In a double-blind, placebo-controlled crossover study with 16 healthy young adults, MDMA alone boosted speed without affecting accuracy and caused arousal, while alcohol alone slowed both speed and accuracy and induced sedation. When taken together, the combination reversed alcohol-induced sedation and improved speed, but accuracy remained significantly impaired. The effects peaked 90–150 minutes after MDMA administration and then declined, except for alcohol sedation, which emerged fully after the infusion stopped. This mismatch between perceived performance and actual impairment may affect neuropsychological functioning.

Psychedelic symptoms of cannabis and cocaine use as a function of trait impulsivity

Journal of Psychopharmacology January 8, 2015 JHP van Wel, DB Spronk, Kim P. C. Kuypers et al. 23 citations

Regular drug users with normal or high trait impulsivity levels showed largely similar subjective responses to cocaine, cannabis, and placebo. Cannabis increased dissociation, psychedelic symptoms, fatigue, confusion, depression, and anxiety while decreasing arousal, positive mood, vigor, friendliness, and elation. Cocaine increased dissociation, psychedelic symptoms, vigor, friendliness, elation, positive mood, anxiety, and arousal while decreasing fatigue. Only a few subjective measures differed by impulsivity level; psychedelic symptoms were most intense in high-impulsivity subjects. Trait impulsivity correlated negatively with vigor (r = -.197) and positively with loss of thought control (r = .237) during cannabis intoxication, but a broad association between trait impulsivity and psychedelic drug experience was absent.