Cognitive and physiological effects of 3,4-methylenedioxymethamphetamine (MDMA or 'ecstasy') in combination with alcohol or cannabis in humans.

Contains fulltext : 74937.pdf (publisher's version ) (Open Access)RU Radboud Universiteit Nijmegen, 7 oktober 2009Promotores : Buitelaar, J.K., Gerven, J.M.A. van Co-promotor : Verkes, R.J.197 p

A review of acute effects of 3,4-methylenedioxymethamphetamine in healthy volunteers.

Contains fulltext : 49563.pdf (publisher's version ) (Closed access)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 .rst 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 dosenresponse 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

The acute effects of MDMA and ethanol administration on electrophysiological correlates of performance monitoring in healthy volunteers

Item does not contain fulltextRATIONALE: Knowing how commonly used drugs affect performance monitoring is of great importance, because drug use is often associated with compromised behavioral control. Two of the most commonly used recreational drugs in the western world, 3,4-methylenedioxymethamphetamine (MDMA or "ecstasy") and ethanol (alcohol), are also often used in combination. The error-related negativity (ERN), correct-related negativity (CRN), and N2 are electrophysiological indices of performance monitoring. OBJECTIVES: The present study aimed to investigate how ethanol, MDMA, and their co-administration affect performance monitoring as indexed by the electrophysiological correlates. METHODS: Behavioral and EEG data were obtained from 14 healthy volunteers during execution of a speeded choice-reaction-time task after administration of ethanol, MDMA, and combined ethanol and MDMA, in a double-blind, placebo-controlled, randomized crossover design. RESULTS: Ethanol significantly reduced ERN amplitudes, while administration of MDMA did not affect the ERN. Co-administration of MDMA and ethanol did not further impair nor ameliorate the effect of ethanol alone. No drug effects on CRN nor N2 were observed. DISCUSSION: A decreased ERN following ethanol administration is in line with previous work and offers further support for the impairing effects of alcohol intoxication on performance monitoring. This impairment may underlie maladaptive behavior in people who are under influence. Moreover, these data demonstrate for the first time that MDMA does not affect performance monitoring nor does it interact with ethanol in this process. These findings corroborate the notion that MDMA leaves central executive functions relatively unaffected

Preserved learning curing the symbol-digit substitution test in patients with schizophrenia, age-matchec controls, and elcerly

Contains fulltext : 148872.pdf (publisher's version ) (Open Access)Objective: Speed of processing, one of the main cognitive deficits in schizophrenia is most frequently measured with a digit symbol-coding test. Performance on this test is additionally affected by writing speed and the rate at which symbol digit relationships are learned, two factors that may be impaired in schizophrenia. This study aims to investigate the effects of sensorimotor speed, short-term learning, and long-term learning on task performance in schizophrenia. In addition, the study aims to explore differences in learning effects between patients with schizophrenia and elderly individuals. Methods: Patients with schizophrenia (N = 30) were compared with age-matched healthy controls (N = 30) and healthy elderly volunteers (N = 30) during the Symbol Digit Substitution Test (SDST). The task was administered on a digitizing tablet, allowing precise measurements of the time taken to write each digit (writing time) and the time to decode symbols into their corresponding digits (matching time). The SDST was administered on three separate days (day 1, day 2, day 7). Symbol digit repetitions during the task represented short-term learning and repeating the task on different days represented long-term learning. Results: The repetition of the same symbol digit combinations within one test and the repetition of the test over days resulted in significant decreases in matching time. Interestingly, these short-term and long-term learning effects were about equal among the three groups. Individual participants showed a large variation in the rate of short-term learning. In general, patients with schizophrenia had the longest matching time whereas the elderly had the longest writing time. Writing time remained the same over repeated testing. Conclusion: The rate of learning and sensorimotor speed was found to have a substantial influence on the SDST score. However, a large individual variation in learning rate should be taken into account in the interpretation of task scores for processing speed. Equal learning rates among the three groups suggest that unintentional learning in schizophrenia and in the elderly is preserved. These findings are important for the design of rehabilitation programs for schizophrenia.9 p

Stable schizophrenia patients learn equally well as age-matched controls and better than elderly controls in two sensorimotor rotary pursuit tasks

Contains fulltext : 151210.pdf (publisher's version ) (Open Access)Objective: To compare sensorimotor performance and learning in stable schizophrenia patients, healthy age- and sex-matched controls and elderly controls on two variations of the rotary pursuit: circle pursuit (true motor learning) and figure pursuit (motor and sequence learning). Method: In the circle pursuit, a target circle, rotating with increasing speed along a predictable circular path on the computer screen, must be followed by a cursor controlled by a pen on a writing tablet. In the eight-trial figure pursuit, subjects learn to draw a complex figure by pursuing the target circle that moves along an invisible trajectory between and around several goals. Tasks were administered thrice (day 1, day 2, day 7) to 30 patients with stable schizophrenia (S), 30 healthy age- and sex-matched controls (C), and 30 elderly participants (>65 years; E) and recorded with a digitizing tablet and pressure-sensitive pen. The outcome measure accuracy (% of time that cursor is within the target) was used to assess performance. Results: We observed significant group differences in accuracy, both in circle and figure pursuit tasks (E < S < C, p < 0.01). Strong learning effects were found in each group. Learning curves were similar in circle pursuit but differed between groups in figure pursuit. When corrected for group differences in starting level, the learning gains over the three sessions of schizophrenia patients and age-matched controls were equal and both were larger than those of the elderly controls. Conclusion: Despite the reduced sensorimotor performance that was found in the schizophrenia patients, their sensorimotor learning seems to be preserved. The relevance of this finding for the evaluation of procedural learning in schizophrenia is discussed. The better performance and learning rate of the patients compared to the elderly controls was unexpected and deserves further study.12 p

Farmacotherapie bij verslaving

Item does not contain fulltext260 p