Psychopharmacology
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Randomized Controlled Trial
Acute effects of THC on time perception in frequent and infrequent cannabis users.
Cannabinoids have been shown to alter time perception, but existing literature has several limitations. Few studies have included both time estimation and production tasks, few control for subvocal counting, most had small sample sizes, some did not record subjects' cannabis use, many tested only one dose, and used either oral or inhaled administration of Δ⁹-tetrahydrocannabinol (THC), leading to variable pharmacokinetics, and some used whole-plant cannabis containing cannabinoids other than THC. Our study attempted to address these limitations. ⋯ A psychoactive dose of THC increases internal clock speed as indicated by time overestimation and underproduction. This effect is not dose related and is blunted in chronic cannabis smokers who did not otherwise have altered baseline time perception.
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Clinical Trial
Cognitive effects of intramuscular ketamine and oral triazolam in healthy volunteers.
Several studies have documented impairments in memory processes as a result of ketamine administration; however, few studies have compared the profile of cognitive effects of ketamine to other drugs. ⋯ Ketamine produces less cognitive impairment than triazolam at doses that produced greater subjective effects. Thus ketamine does not produce the underestimation of cognitive impairment typically seen with triazolam.
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Behavioral-economic demand curve analysis offers several useful measures of drug self-administration. Although generation of demand curves previously required multiple days, recent within-session procedures allow curve construction from a single 110-min cocaine self-administration session, making behavioral-economic analyses available to a broad range of self-administration experiments. However, a mathematical approach of curve fitting has not been reported for the within-session threshold procedure. ⋯ The exponential demand equation can be fit to single-session data using the threshold procedure for cocaine self-administration. Removing data points that occur during relatively unstable brain cocaine concentrations resulted in more accurate estimates of demand curve slope than graphical methods, permitting a more comprehensive analysis of drug self-administration via a behavioral-economic framework.
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Randomized Controlled Trial
Human pharmacology of 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) after repeated doses taken 2 h apart.
3,4-methylenedioxymethamphetamine (MDMA, ecstasy) is one of the most abused recreational drugs. Its usual pattern of misuse includes repeated doses taken over a short time period that could influence MDMA pharmacology and toxicity. ⋯ MDMA pharmacokinetics and metabolic disposition following two doses separated by 2 h show that the contribution of the first dose to the MDMA-induced mechanism-based metabolic inhibition was already apparent. The concentrations of MDMA after the second dose were slightly higher than expected. The effects on blood pressure and temperature after the second administration were slightly higher than those following the first, but for heart rate and subjective variables these were lower than expected considering the MDMA concentrations achieved, suggesting a possible tolerance phenomenon.
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Randomized Controlled Trial
Docosahexaenoic acid-concentrated fish oil supplementation in subjects with mild cognitive impairment (MCI): a 12-month randomised, double-blind, placebo-controlled trial.
Epidemiological studies have suggested a beneficial effect of fish oil supplementation in halting the initial progression of Alzheimer's disease. However, it remains unclear whether fish oil affects cognitive function in older people with mild cognitive impairment (MCI). ⋯ This study suggested the potential role of fish oil to improve memory function in MCI subjects. Studies with larger sample sizes, longer intervention periods, different fish oil dosages and genetic determinations should be investigated before definite recommendations can be made.