9 results on '"Dumont, G. J. H."'
Search Results
2. Acute neuropsychological effects of MDMA and ethanol (co-)administration in healthy volunteers
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Dumont, G. J. H., Wezenberg, E., Valkenberg, M. M. G. J., de Jong, C. A. J., Buitelaar, J. K., van Gerven, J. M. A., and Verkes, R. J.
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- 2008
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3. Biomarkers for the effects of selective serotonin reuptake inhibitors (SSRIs) in healthy subjects
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Dumont, G. J. H., de Visser, S. J., Cohen, A. F., and van Gerven, J. M. A.
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- 2005
4. Acute psychomotor, memory and subjective effects of MDMA and THC co-administration over time in healthy volunteers.
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Dumont, G. J. H., Hasselt, J. G. C. van, De Kam, M., Gerven, J. M. A. van, Touw, D. J., Buitelaar, J. K., and Verkes, R. J.
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ECSTASY (Drug) , *PSYCHOMOTOR disorders , *TETRAHYDROCANNABINOL , *PHARMACOKINETICS , *MEMORY , *PLACEBOS , *COGNITIVE ability , *WESTERN society - Abstract
In Western societies a considerable percentage of young people expose themselves to the combination of 3,4-methylenedioxymethamphetamine (MDMA or ‘ecstasy’) and cannabis. The aim of the present study was to assess the acute effects of co-administration of MDMA and THC (the main psychoactive compound of cannabis) on pharmacokinetics, psychomotor performance, memory and subjective experience over time. We performed a four-way, double blind, randomized, crossover, placebo-controlled study in 16 healthy volunteers (12 male, four female) between the ages of 18 and 27. MDMA (100 mg) was given orally, THC (4, 6, and 6 mg, interval of 90 min) was vaporized and inhaled. THC induced more robust cognitive impairment compared with MDMA, and co-administration did not exacerbate single drug effects on cognitive function. However, co-administration of THC with MDMA increased desired subjective drug effects and drug strength compared with the MDMA condition, which may explain the widespread use of this combination. [ABSTRACT FROM PUBLISHER]
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- 2011
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5. Acute psychomotor effects of MDMA and ethanol (co-) administration over time in healthy volunteers.
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Dumont, G. J. H., Schoemaker, R. C., Touw, D. J., Sweep, F. C. G. J., Buitelaar, J. K., van Gerven, J. M. A., and Verkes, R. J.
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ECSTASY (Drug) , *PSYCHOPHARMACOLOGY , *PHARMACODYNAMICS , *PHARMACOKINETICS , *ALCOHOL in the body , *PHYSIOLOGY - Abstract
In Western societies, a considerable percentage of young people use 3,4-methylenedioxymethamphetamine (MDMA or 'ecstasy'). The use of alcohol (ethanol) in combination with ecstasy is common. The aim of the present study was to assess the acute psychomotor and subjective effects of (co-) administration of MDMA and ethanol over time and in relation to the pharmacokinetics. We performed a four-way, double blind, randomized, crossover, placebo-controlled study in 16 healthy volunteers (nine men, seven women) between the ages of 18 and 29. MDMA (100 mg) was given orally while blood alcohol concentration was maintained at pseudo-steady state levels of approximately 0.6‰ for 3 h by a 10% intravenous ethanol clamp. MDMA significantly increased psychomotor speed but did not affect psychomotor accuracy and induced subjective arousal. Ethanol impaired both psychomotor speed and accuracy and induced sedation. Coadministration of ethanol and MDMA improved psychomotor speed but impaired psychomotor accuracy compared with placebo and reversed ethanol-induced sedation. Pharmacokinetics and pharmacodynamics showed maximal effects at 90-150 min after MDMA administration after which drug effects declined in spite of persisting MDMA plasma concentration, with the exception of ethanol-induced sedation, which manifested itself fully only after the infusion was stopped. In conclusion, results show that subjects were more aroused when intoxicated with both substances combined compared with placebo, but psychomotor accuracy was significantly impaired. These findings may have implications for general neuropsychological functioning as this may provide a sense of adequate performance that does not agree with a significant reduction in psychomotor accuracy. [ABSTRACT FROM AUTHOR]
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- 2010
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6. Ethanol co-administration moderates 3,4-methylenedioxymethamphetamine effects on human physiology.
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Dumont, G. J. H., Kramers, C., Sweep, F. C. G. J., Willemsen, J. J., Touw, D. J., Schoemaker, R. C., van Gerven, J. M. A., Buitelaar, J. K., and Verkes, R. J.
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PHYSIOLOGICAL effects of alcohol , *PSYCHOPHARMACOLOGY , *ECSTASY (Drug) , *ALCOHOL in the body , *PHARMACODYNAMICS , *PHYSIOLOGY - Abstract
Alcohol is frequently used in combination with 3,4-methylenedioxymethamphetamine (MDMA). Both drugs affect cardiovascular function, hydration and temperature regulation, but may have partly opposing effects. The present study aims to assess the acute physiologic effects of (co-) administration of MDMA and ethanol over time. A fourway, double blind, randomized, crossover, placebo-controlled study in 16 healthy volunteers (9 male and 7 female) between the ages of 18 and 29. MDMA (100 mg) was given orally and blood ethanol concentration was maintained at pseudo-steady state levels of 0.6‰ by a three-hour 10% intravenous ethanol clamp. Cardiovascular function, temperature and hydration measures were recorded throughout the study days. Ethanol did not significantly affect physiologic function, with the exception of a short lasting increase in heart rate. MDMA potently increased heart rate and blood pressure and induced fluid retention as well as an increase in temperature. Co-administration of ethanol with MDMA did not affect cardiovascular function compared to the MDMA alone condition, but attenuated the effects of MDMA on fluid retention and showed a trend for attenuation of MDMA-induced temperature increase. In conclusion, coadministration of ethanol and MDMA did not exacerbate physiologic effects compared to all other drug conditions, and moderated some effects of MDMA alone. [ABSTRACT FROM AUTHOR]
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- 2010
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7. Increased oxytocin concentrations and prosocial feelings in humans after ecstasy (3,4-methylenedioxymethamphetamine) administration.
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Dumont, G. J. H., Sweep, F. C. G. J., van der Steen, R., Hermsen, R., Donders, A. R. T., Touw, D. J., van Gerven, J. M. A., Buitelaar, J. K., and Verkes, R. J.
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OXYTOCIN , *OLIGOPEPTIDES , *ECSTASY (Drug) , *METHAMPHETAMINE , *HALLUCINOGENIC drugs - Abstract
MDMA (3,4-methylenedioxymethamphetamine or “ecstasy”) is a recreationally used drug with remarkable and characteristic prosocial effects. In spite of abundant attention in the scientific literature, the mechanism of its prosocial effects has not been elucidated in humans. Recently, research in animals has suggested that the neuropeptide oxytocin may induce these effects. In a double blind, randomized, crossover, and placebo-controlled study in 15 healthy volunteers we assessed blood oxytocin and MDMA concentrations and subjective prosocial effects after oral administration of 100 mg MDMA or placebo. MDMA induced a robust increase of blood oxytocin concentrations and an increase of subjective prosocial feelings. Within subjects, the variations in these feelings were significantly and positively correlated with variation in oxytocin levels, and the correlations between these feelings and oxytocin were significantly stronger than those between these feelings and blood MDMA levels. MDMA induces oxytocin release in humans, which may be involved in the characteristic prosocial effects of ecstasy. [ABSTRACT FROM AUTHOR]
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- 2009
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8. A review of acute effects of 3,4-methylenedioxymethamphetamine in healthy volunteers.
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Dumont, G. J. H. and Verkes, R. J.
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ECSTASY (Drug) , *DRUG abuse , *METHAMPHETAMINE , *PSYCHOPHARMACOLOGY , *HYDROCORTISONE - Abstract
This review of the literature aims to identify the acute effects of MDMA (ecstasy) in healthy volunteers. The wide range of relevant but methodologically diverse tests was first grouped into clusters to allow an evaluation of tests that would otherwise have been excluded due to their low frequency of utilization. The following three types of tests were evaluated: (1) functional tests quantifying executive, attention, visual, motor, visuomotor and auditory functions, (2) phenomenological tests assessing personal, subjective experiences, and (3) physiological measures reflecting neurophysiological, endocrine and physiological parameters. MDMA showed robust effects on most of the phenomenological and physiological tests. Functional tests were scarce, preventing any meaningful conclusions to be drawn from their evaluation other than that these tests should be incorporated into future acute-effect studies. A striking dose-response relationship appeared for cardiovascular effects. At doses below 1.0 mg/kg MDMA no change was observed relative to placebo while above this dose all studies reported significant increases. Furthermore, pupil size, plasma cortisol and plasma prolactin levels proved responsive to MDMA administration. The reported subjective effects of MDMA matched the entactogenic profile. Although interest in the action of MDMA is considerable, the existing knowledge about the cognitive effects of MDMA in humans is still rather limited and further research into the drug's effects is recommended, also in view of potential therapeutic uses of the drug. [ABSTRACT FROM AUTHOR]
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- 2006
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9. Acute MDMA and ethanol interaction effects on psychomotor performance.
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Dumont, G. J. H., Valkenberg, M. M. G. J., Schoemaker, R., Buitelaar, J. K., van Gerven, J. M. A., and Verkes, R. J.
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ECSTASY (Drug) , *ALCOHOL , *DRUG interactions , *DRUG side effects , *MOTOR ability , *SACCADIC eye movements - Abstract
Introduction: A considerable percentage of young people expose themselves to 3,4-methylenedioxy-methamphetamine (MDMA or ‘ecstasy’). Alcohol is relatively commonly used in combination with MDMA ( Barrett et al., 2005 ). As a percentage of MDMA users admit to driving under influence ( Riley et al., 2001 ), the assessment of the effects of co-administration of these substances on psychomotor performance is warranted. Hypothesis: We hypothesized that the co-administration of MDMA and ethanol would ameliorate the impairment induced by ethanol alone. Methods: We performed a double-blind, randomized, placebo- controlled study in 16 healthy volunteers (9 male, 7 female) in the age of 18–29 years. MDMA 100 mg was given orally and blood alcohol concentration (BAC) was maintained at 0.6‰ by a three hour 10% alcohol infusion regime (adjustment of infusion rate according to regular sampled breath alcohol concentration). Saccadic and smooth pursuit eye movements, a validated measure of ethanol induced sedation ( van Steveninck et al., 1999 ), were recorded using Nihon Kohden® and Cambridge Electronic Design (CED®) hardware and Spike2® software at 1 : 35 post drug administration. Results were statistically evaluated using GLM in SPSS® 11.5. Results: Results are presented in table 1 . Saccadic peak velocity was increased after MDMA (p=0.000). Co-administration showed significant increase in peak saccadic velocity compared to placebo (p=0.004), although significantly less then the increase as observed after MDMA alone (p=0.003). Smooth pursuit was significantly impaired after ethanol compared to placebo (p=0.000) and MDMA (p=0.000), co-adminstration also impaired score compared to placebo (p=0.000) and MDMA (p=0.000). Conclusions: MDMA induced arousal as measured by the saccadic peak velocity when administered alone and, to a lesser degree, in combination with ethanol. Co-administration of MDMA with ethanol however could not ameliorate the deterioration of psychomotor accuracy by ethanol as measured by smooth pursuit eye movements. These findings suggest that although MDMA might ameliorate ethanol induced sedation it does not ameliorate impaired psychomotor skills. This might give a false sense of improved performance while intoxicated and thus increases risks of for example road accidents. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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