Cannabis-influenced driving performance is significantly different from alcohol-induced driving behavior, according to driving simulator data published in the Journal of Applied Toxicology.
Investigators with the National Institute on Drug Abuse and the University of Iowa evaluated simulated driving performance in subjects following their consumption of vaporized cannabis, alcohol, or placebo.
Researchers reported that cannabis administration was associated compensatory driving behavior, such as decreased mean speed and increased mean following distance, whereas alcohol administration was associated with faster driving. Their findings are similar to those of other driving studies, like those here and here.
Investigators also reported that cannabis dosing in combination with low quantities of alcohol “mitigated drivers’ tendency to drive faster with alcohol” – a finding that contrasts with prior data acknowledging that the two substances combined typically possess an additive adverse effect on psychomotor performance.
“THC concentration-dependent associations with decreased speed, increased time below the speed limit and increased following distance suggest possible awareness by drivers of potential impairment and attempts to compensate,” authors concluded. “The compensatory behavior exhibited by cannabis-influenced drivers distinctly contrasts with an alcohol-induced higher risk behavior, evidenced by greater percent speed.”
According to the findings of a recently published literature review of crash culpability studies, “[A]cute cannabis intoxication is related to a statistically significant risk increase of low to moderate magnitude [odds ratio between 1.2 and 1.4].” By contrast, a 2015 case-control study by the US National Highway Traffic Safety Administration reported that driving with legal amounts of booze in one’s system is associated with a nearly four-fold increased crash risk (odds ratio = 3.93).
An abstract of the study, “Cannabis effects on driving longitudinal control with and without alcohol,” appears online here.
NORML reviews the top news stories of 2015.
#1 Congress Reauthorizes Medical Marijuana Protections
Members of Congress approved language in the fiscal year 2016 omnibus spending bill that continues to limit the federal government from taking punitive action against state-licensed individuals or operations that are acting are in full compliance with the medical marijuana laws of their states. The provisions reauthorize Section 538 of the Continuing Appropriations Act of 2015, which states, "None of the funds made available in this act to the Department of Justice may be used … to prevent … states … from implementing their own state laws that authorize the use, distribution, possession, or cultivation of medical marijuana."
#2 Federal Judge Upholds Marijuana’s Schedule I Status
A federal judge in April rejected a motion challenging the constitutionality of cannabis’ classification as a Schedule I prohibited substance. "At some point in time, a court may decide this status to be unconstitutional," Judge Kimberly Mueller said from the bench. "But this is not the court and not the time." Judge Meuller had presided over five days of hearings in October 2014 in a challenge brought by members of the NORML Legal Committee.
#3 Medical Cannabis Access Associated With Less Opioid Abuse
States that permit qualified patients to access medical marijuana via dispensaries possess lower rates of opioid addiction and overdose deaths, according to a study published in July by the National Bureau of Economic Research, a non-partisan think-tank. The findings mirror those published in 2014 in The Journal of the American Medical Association concluding, "States with medical cannabis laws had a 24.8 percent lower mean annual opioid overdose mortality rate compared with states without medical cannabis laws."
#4 DC Depenalizes Marijuana; Arrests Plummet
Despite threats from members of Congress, District officials implemented voter-approved legislation earlier this year eliminating penalties associated with the possession and cultivation of personal use quantities of marijuana by adults. Following the law’s implementation, marijuana-related arrests in the nation’s capital fell 99 percent.
#5 Marijuana Law Changes Don’t Change Youth Use, Attitudes
Rates of youth marijuana use are unaffected by changing laws, according to data published in July in The American Journal of drug and Alcohol Abuse. Investigators evaluated trends in young people’s attitudes toward cannabis and their use of the substance during the years 2002 to 2013 – a time period where 14 states enacted laws legalizing the medical use of the plant, and two states approved its recreational use by adults. "Our results may suggest that recent changes in public policy, including the decriminalization, medicalization, and legalization of marijuana in cities and states across the country, have not resulted in more use or greater approval of marijuana use among younger adolescents," researchers reported.
#6 Gallup Poll: More Americans Than Ever Say Marijuana Should Be Legal
Fifty-eight percent of Americans believe that "the use of marijuana should be made legal," according to nationwide survey data released in October by Gallup pollsters. The percentage ties the highest level of support ever reported by Gallup, which has been measuring Americans’ attitudes toward cannabis since the late 1960s. The percentage is more than twice the level of support reported in the mid-1990s.
#7 Study: Marijuana Use Not Associated With Changes In Brain Morphology
Marijuana use is not associated with structural changes in the brain, according to imaging data published in January in The Journal of Neuroscience. Investigators assessed brain morphology in both daily adult and adolescent cannabis users compared to non-users. They found "no statistically significant differences … between daily users and nonusers on volume or shape in the regions of interest" after researchers controlled for participants’ use of alcohol. "[T]he results indicate that, when carefully controlling for alcohol use, gender, age, and other variables, there is no association between marijuana use and standard volumetric or shape measurements of subcortical structures," researchers reported.
#8 Marijuana Consumers Less Likely To Be Obese, Suffer Diabetes Risk
Those who consume cannabis are 50 percent less likely to suffer from metabolic syndrome as compared to those who do not, according to findings published in November in The American Journal of Medicine. Metabolic syndrome is a group of risk factors, including high blood pressure, high blood sugar, unhealthy cholesterol levels, and abdominal fat, which are linked to increased risk of heart disease and adult onset diabetes, among other serious health consequences. The findings are similar to those of previous studies reporting that those who use cannabis are less likely to be obese or suffer from diabetes.
#9 NHTSA: THC-Positive Drivers Don’t Possesses Elevated Crash Risk
Drivers who test positive for the presence of THC in their blood are no more likely to be involved in motor vehicle crashes than are drug-free drivers, according to a case-control study released in February by the United States National Highway Transportation and Safety Administration. Authors reported that drivers who tested positive for the presence of THC possessed an unadjusted, elevated risk of accident of 25 percent (Odds Ratio=1.25) compared to controls (drivers who tested negative for any drug or alcohol). However, this elevated risk became insignificant (OR=1.05) after investigators adjusted for demographic variables, such as the drivers’ age and gender. The study is the largest of its kind ever conducted in the United States.
#10 Legal Marijuana States Collect Over $200 Million In New Tax Revenue
Taxes on the legal production and sale of cannabis in the states of Colorado and Washington have yielded over $200 million in new revenue since going into effect in 2014, according to calculations reported by The Huffington Post in September. Colorado collected more than $117 million dollars from marijuana sales while Washington collected over $83 million. Cannabis sales commenced in Oregon in on October 1, 2015 and have yet to begin in Alaska.
Republican Gov. Bruce Rauner on Friday issued an amendatory veto to House Bill 218, which seeks to decriminalize minor marijuana possession offenses.
As initially approved by the legislature in May, HB 218 reduced personal use possession penalties (up to 15 grams) from a Class A criminal misdemeanor, punishable by up to 6 months in jail, a $1,500 fine, and a criminal record, to a petty offense, punishable by a fine only (up to $125.00) – no arrest, and no criminal record. Governor Rauner’s amendatory veto seeks to decrease the proposed possession limits from 15 grams to 10 grams, whole also seeking to raise fines to $200.00.
Governor Rauner also seeks to lower the state’s proposed per se THC/blood limit from 15ng/ml to 5ng/ml. Under present Illinois law, drivers with any detectable amount of THC in their blood are in violation of the state’s traffic safety laws.
If a majority of lawmakers fail to approve of the Governor’s amendments, the measure will be dead for this year’s legislative session.
To date, 20 states and Washington, DC have passed legislation eliminating the threat of incarceration for marijuana possession offenses via either legalization or decriminalization.
Drivers who test positive for the presence of THC in blood are no more likely to be involved in motor vehicle crashes than are drug-free drivers, according to a federally sponsored case-control study involving some 9,000 participants. The study, published Friday by the United States National Highway Traffic Administration (NHTSA), is the first large-scale case-control study ever conducted in the United States to assess the crash risk associated with both drugs and alcohol use by drivers.
Authors reported that drivers who tested positive for any amount of THC possessed an unadjusted, elevated risk of accident of 25 percent (Odds Ratio=1.25) compared to controls (drivers who tested negative for any drug or alcohol). However, this elevated risk became insignificant (OR=1.05) after investigators adjusted for demographic variables, such as the drivers’ age and gender. After researchers controlled for both demographic variables and the presence of alcohol, THC-positive drivers’ elevated risk of accident was zero (OR=1).
By contrast, researchers reported that drivers who tested positive for low levels of alcohol possessed a statistically significant risk of accident, even after controlling for demographic variables (e.g., Drivers with a BAC of 0.03 possessed a 20 percent greater risk of motor vehicle accident [OR=1.20] compared to controls). Drivers with BAC levels of 0.05 possessed a greater than two-fold risk of accident (OR=2.07) while motorists with BAC levels of 0.08 possessed a nearly four-fold risk of accident (OR=3.93).
Researchers did not analyze drivers’ THC levels to similarly estimate whether higher or lower THC levels may impact crash risk in a dose-dependent manner, as has been previously reported in some separate analyses of fatal crash data.
Authors concluded, “This finding indicates that these other variables (age, gender, ethnicity, and alcohol use) were highly correlated with drug use and account for much of the increased (crash) risk associated with the use of illegal drugs and THC.”
The study’s finding contradict allegations by NIDA and others that “marijuana use more than doubles a driver’s risk of being in an accident,” but are largely consistent with those of a 2013 literature review published in the journal Accident Analysis and Prevention which reported that cannabis-positive drivers did not possess a statistically significant risk of a either fatal accident or a motor vehicle accident causing injury.
See NORML’s white paper on cannabis and psychomotor performance here.
The Arizona Supreme Court this week rejected a 1990 state law that classified the presence of inert THC metabolites in blood or urine as a per se traffic safety violation.
Carboxy-THC, the primary metabolite (breakdown product) of THC is not psychoactive. Because it is lipid soluble, the metabolite may remain detectable in blood or urine for periods of time that extend well beyond any suspected period of impairment. As a result, the US National Highway Traffic Safety Administration acknowledges, “It is … currently impossible to predict specific effects based on THC-COOH concentrations.”
Nonetheless, under Arizona law, the mere presence of carboxy THC — absent any evidence of behavioral impairment — was considered to be a criminal violation of the state’s traffic safety laws. (Delaware, Georgia, Illinois, Indiana, Iowa, Nevada, Ohio, Oklahoma, Rhode Island, and Utah impose similar statutes.) On Wednesday, the Court struck down the provision.
Writing for the majority, Justice Robert Brutinel opined: “The State’s interpretation that ‘its metabolite’ includes any byproduct of a drug listed in § 13-3401 found in a driver’s system leads to absurd results. … Most notably, this interpretation would create criminal liability regardless of how long the metabolite remains in the driver’s system or whether it has any impairing effect. For example, at oral argument the State acknowledged that, under its reading of the statute, if a metabolite could be detected five years after ingesting a proscribed drug, a driver who tested positive for trace elements of a non-impairing substance could be prosecuted.”
He added: “Additionally, this interpretation would criminalize otherwise legal conduct. In 2010, Arizona voters passed the Arizona Medical Marijuana Act (“AMMA”), legalizing marijuana for medicinal purposes. Despite the legality of such use, and because § 28-1381(A)(3) does not require the State to prove that the marijuana was illegally ingested, prosecutors can charge legal users under the (A)(3) provision. Because carboxy-THC can remain in the body for as many as twenty-eight to thirty days after ingestion, the State’s position suggests that a medical-marijuana user could face prosecution for driving any time nearly a month after they had legally ingested marijuana.”
The Court concluded: “Because the legislature intended to prevent impaired driving, we hold that the ‘metabolite’ reference in § 28-1381(A)(3) is limited to any of a proscribed substance’s metabolites that are capable of causing impairment. Accordingly, … drivers cannot be convicted of the (A)(3) offense based merely on the presence of a non-impairing metabolite that may reflect the prior usage of marijuana.”
The Court did not address provisions in the state’s per se DUI law outlawing the operation of a motor vehicle with any presence of THC in one’s blood even though, according to NHTSA, “It is difficult to establish a relationship between a person’s THC blood or plasma concentration and performance impairing effects.”