Study: Elevated THC Blood Levels Persist for Days in Habitual Cannabis Consumers

By Paul Armentano, NORML

VICTORIA, AUSTRALIAblood — The presence of THC may persist in the blood of habitual cannabis consumers for multiple days at concentrations above 5ng/ml, according clinical data recently published in the journal Forensic Science International.

Australian researchers assessed daily concentrations of THC in the blood of 21 subjects over a period of 7 days of monitored abstinence. Subjects reported having engaging in the “heavy” use of cannabis during the months leading up to the study.

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Zero Tolerance Driving Policy for Cannabis Struck Down by Arizona Supreme Court

By Associated Press

Authorities can’t prosecute Arizona motorists for driving under the influence of marijuana unless the person is impaired at the time of the stop, the state Supreme Court ruled Tuesdaygavel in the latest opinion on an issue that several states have grappled with across the nation.

The ruling overturned a state Court of Appeals decision last year that upheld the right of authorities to prosecute pot smokers for DUI even when there is no evidence of impairment.

The opinion focuses on two chemical compounds in marijuana that show up in blood and urine tests — one that causes impairment and one that doesn’t but stays in a pot user’s system for weeks.

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Study: Cannabis Least Likely Substance To Elevate Vehicle Crash Risk

By Paul Armentano, Deputy Director, NORML

The presence of various controlled substances in blood is associated with an increased risk of fatal crash involvement, according to data published online in the journal Accident Analysis and Prevention.safe_driving

Investigators at Columbia University conducted a case-control study to assess the association between drug use and fatal crash risk. Of the substances identified by researchers, authors reported that depressants were most likely to be associated with crash risk (estimated odds ratio = 4.83). Estimated odds ratios for other specific drug categories were 3.57 for stimulants, 3.41 for polydrug use (excluding alcohol), and 3.03 for narcotics. Marijuana (1.83) possessed the lowest odds ratios of the substances identified.

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