Tag: carboxy THC

THC Metabolite Concentration is Inconsistent Predictor of Impairment

Are blood or saliva concentrations of delta-9 THC metabolites predictive of impairment? That’s what a recent article in the Neuroscience and Biobehavioral Reviews journal sought to determine. The article published data from a meta-regression analysis of 28 studies involving 824 participants. The biggest takeaway is that neither THC nor THC metabolite concentrations are consistent predictors of impairment.  Surprisingly, THC levels in blood, which is the bodily specimen of choice in OWI search warrants in Iowa, showed the weakest correlation. Iowa law equates the mere presence of inactive metabolites of THC with being under the influence of cannabis.  However, the science […]

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Marijuana and Alcohol Combine to Affect Driving Performance

The February 5, 2021 issue of Psychopharmacology published data from a Canadian study assessing the effect of both THC and alcohol on driving performance. Regular users of cannabis participated in simulated driving sessions after smoking marijuana (12.5% THC) and drinking alcohol (target breath alcohol 0.08%). Researchers discovered the driving performance after ingesting both marijuana and alcohol “was significantly greater than the effect of each drug by itself.”  This included the test subjects’ reaction time as well as their ability to maintain speed and lateral position.  The suggested additive effect of marijuana and alcohol on driving performance is consistent with prior […]

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THC Levels Do Not Predict Driving Impairment

The February 5, 2021 issue of Traffic Injury Prevention published results from an Australian study assessing the relationship between THC levels and driving performance.   Volunteers consumed vaporized cannabis samples of varying potencies containing THC, CBD and a placebo.  Blood and saliva samples were collected 30 minutes after inhalation and 3.5 hours later.  Researchers evaluated driving performance on a simulator. Nearly half of the participants failed to show driving impairment after 30 minutes despite showing THC levels above the per se limits, e.g., 5 ng/ml.  Several participants did show impairment at the 3.5 hour mark, but their THC levels were below […]

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THC Metabolites Detected in Urine Following Full-Spectrum CBD Use

The November 4, 2020 issue of JAMA Psychiatry published results from a recent study examining whether the use of full-spectrum CBD from legal hemp (< 0.30% Δ9-THC) would lead to positive urine test results for THC metabolites. It has been often assumed that hemp-derived cannabidiol products will test negative for urinary THC.  However, the study showed that half of subjects tested positive for carboxy-THC, an inactive metabolite of Δ9-THC, after four weeks of daily use.  Samples were initially screened through urine drug assays.  Positive screens were confirmed through gas chromatography-mass spectroscopy. The results suggest that individuals consistently using full-spectrum, hemp-derived […]

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