Psychopharmacology
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Randomized Controlled Trial
Preliminary evidence of cannabinoid effects on brain-derived neurotrophic factor (BDNF) levels in humans.
Acute and chronic exposure to cannabinoids has been associated with cognitive deficits, a higher risk for schizophrenia and other drug abuse. However, the precise mechanism underlying such effects is not known. Preclinical studies suggest that cannabinoids modulate brain-derived neurotrophic factor (BDNF). Accordingly, we hypothesized that Delta(9)-tetrahydrocannabinol (Delta(9)-THC), the principal active component of cannabis, would alter BDNF levels in humans. ⋯ The effects of socially relevant doses of cannabinoids on BDNF suggest a possible mechanism underlying the consequences of exposure to cannabis. This may be of particular importance for the developing brain and also in disorders believed to involve altered neurodevelopment such as schizophrenia. Larger studies to investigate the effects of cannabinoids on BDNF and other neurotrophins are warranted.
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Randomized Controlled Trial
The incidence of unpleasant dreams after sub-anaesthetic ketamine.
Ketamine is an N-methyl-D: -aspartate (NMDA) receptor antagonist with psychotogenic effects and for which there are diverse reports of whether pleasant or unpleasant dreams result during anaesthesia, post-operatively or after sub-anaesthetic use. ⋯ Ketamine causes unpleasant dreams over the three post-administration nights. This may be evidence of a residual psychotogenic effect that is not found on standard self-report symptomatology measures or a result of disturbed sleep electrophysiology.
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Performance of cognitive tasks in nonhuman primates (NHPs) requires specific brain regions to make decisions under different degrees of difficulty or "cognitive load." ⋯ The findings provide insight into how cognition is enhanced by CX717 in terms of brain, and underlying neural, processes that are activated on high vs. low cognitive load trials.
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Abrupt cessation of caffeine often results in several withdrawal symptoms among habitual caffeine consumers. ⋯ The 14 well-described caffeine withdrawal symptoms factor into three clusters, suggesting the existence of three distinct underlying mechanisms of caffeine withdrawal. Increasing habitual caffeine consumption is associated with an increased likelihood of reporting the fatigue and headache and dysphoric mood symptoms, but not the flu-like somatic symptoms.
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Randomized Controlled Trial
Delta-9-tetrahydrocannabinol (THC) serum concentrations and pharmacological effects in males after smoking a combination of tobacco and cannabis containing up to 69 mg THC.
Delta9-Tetrahydrocannabinol (THC) is the main active constituent of cannabis. In recent years, the average THC content of some cannabis cigarettes has increased up to approximately 60 mg per cigarette (20% THC cigarettes). The pharmacokinetics of THC after smoking cannabis cigarettes containing more than approximately 35 mg THC (3.55% THC cigarettes) is unknown. To be able to perform suitable exposure risk analysis, it is important to know if there is a linear relation at higher doses. ⋯ This study demonstrates that the known linear association between THC dose and THC serum concentration also applies for high THC doses.