Cognition and motor control as a function of Δ9-THC concentration in serum and oral fluid: Limits of impairment

Ramaekers, Johannes G.; Moeller, Manfred R.; Ruitenbeek, Peter van; Theunissen, Eef L.; Schneider, E.; Kauert, G.

doi:10.1016/j.drugalcdep.2006.03.015

Cited by 261 publications

(266 citation statements)

References 38 publications

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“…None of these 24-hour studies measured driving performance directly. As described earlier, Ramaekers, Moehler, and colleagues demonstrated that psychomotor testing performance is decreased for up to 5-6 h after smoking marijuana [43]. Although they did not measure past 6 h, the majority of impairment occurred in the first 2 h after smoking, gradually tapering down at hour six.…”

Section: Resultsmentioning

confidence: 83%

“…Ramaekers et al measured performance in subjects after they were administered single doses of 0, 250 and 500 μg/kg THC by smoking [43]. Performance tests included measures of perceptual motor control, motor impulsivity, and cognitive function.…”

Section: Drug Testingmentioning

confidence: 99%

“…Unfortunately, the rapid rise and decline in serum THC make it difficult to use as a marker of intoxication in the setting of real world driving. Serum must be drawn within 2 h of smoking marijuana to have a generally quantifiable concentration of THC; the psychomotor effects of marijuana, however, may exceed this time frame [43,44]. Whereas an undetectable blood alcohol concentration would effectively rule out driving under the influence of alcohol (barring the effects from a hangover), an undetectable THC concentration does not similarly rule out impairment.…”

Section: Drug Testingmentioning

confidence: 99%

“…Whereas an undetectable blood alcohol concentration would effectively rule out driving under the influence of alcohol (barring the effects from a hangover), an undetectable THC concentration does not similarly rule out impairment. Ramaekers et al measured decreased performance compared to placebo up to 6 h after smoking marijuana [43]. In addition, the qualitative measurement of THC-COOH metabolite in urine does not correlate with either time of ingestion or active intoxication.…”

Section: Drug Testingmentioning

confidence: 99%

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Medical Marijuana and Driving: a Review

et al. 2014

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Medical marijuana remains a highly debated treatment regimen despite removal of state penalties against care providers prescribing the drug and patients treated with the drug in many areas of the USA. The utility of marijuana in specific medical conditions has been studied at length, but its effects on driving performance and risk of motor vehicle collision remain unclear. As with other medications that affect psychomotor function, the healthcare provider should be informed of the potential risks of driver safety prior to prescribing this psychotropic drug to give appropriate anticipatory guidance for appropriate use. The goal of this narrative review is to assess the current literature regarding marijuana as it relates to driving performance and traffic safety. With a foundation in the pharmacology of cannabinoids, we consider the limitations of testing cannabinoid and metabolite concentration. In addition, we will review studies on driving performance and epidemiological studies implicating marijuana in motor vehicle collisions. The increasing prevalence of medical marijuana laws in the USA suggests that clinicians should be aware of marijuana's influence on public safety. Patients should abstain from driving for 8 h if they achieve a subjective "high" from self-treatment with smoked marijuana and should be aware of the cumulative effects of alcohol and other psychoactive xenobiotics.

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Section: Resultsmentioning

confidence: 83%

Section: Drug Testingmentioning

confidence: 99%

Section: Drug Testingmentioning

confidence: 99%

Section: Drug Testingmentioning

confidence: 99%

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Medical Marijuana and Driving: a Review

et al. 2014

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“…A further limitation is that blood levels were not monitored following THC exposure, as it cannot be excluded that there is differential peripheral metabolism associated with COMT genotype (eg carriers of the Val allele may have lower levels of peripheral THC metabolism). Further research with a uniform drug administration procedure and direct measures of peripheral levels of THC (in blood or saliva samples; Ramaekers et al, 2006) is warranted.…”

Section: Methodological Issuesmentioning

confidence: 99%

An Experimental Study of Catechol-O-Methyltransferase Val158Met Moderation of Δ-9-Tetrahydrocannabinol-Induced Effects on Psychosis and Cognition

Henquet

Rosa

Krabbendam

et al. 2006

Neuropsychopharmacol

285

210

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Observational studies have suggested that psychometric psychosis liability and a functional polymorphism in the catechol-Omethyltransferase (COMT Val 158 Met) gene moderate the psychosis-inducing effect of cannabis. To replicate and extend this finding, a double-blind, placebo-controlled cross-over design was used in which patients with a psychotic disorder (n ¼ 30), relatives of patients with a psychotic disorder (n ¼ 12), and healthy controls (n ¼ 32) were exposed to D-9-tetrahydrocannabinol (D-9-THC, the principal component of cannabis) or placebo, followed by cognitive assessment and assessment of current psychotic experiences. Previous expression of psychometric psychosis liability was also assessed. Models of current psychotic experiences and cognition were examined with multilevel random regression analyses to assess (i) main effects of genotype and condition, (ii) interactions between condition and genotype, and (iii) three-way interactions between condition, genotype, and psychometric psychosis liability. Carriers of the Val allele were most sensitive to D-9-THC-induced psychotic experiences, but this was conditional on prior evidence of psychometric psychosis liability. D-9-THC impacted negatively on cognitive measures. Carriers of the Val allele were also more sensitive to D-9-THC-induced memory and attention impairments compared to carriers of the Met allele. Experimental effects of D-9-THC on cognition and psychosis are moderated by COMT Val 158 Met genotype, but the effects may in part be conditional on the additional presence of pre-existing psychosis liability. The association between cannabis and psychosis may represent higher order gene-environment and gene-gene interactions.

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