August 4, 2010 – Before deciding that this plant should be legal to smoke, consider the effect on public health, a Stanford expert warns.

You may support California’s Proposition 19, the Regulate, Control and Tax Cannabis Act of 2010, because you think the war on drugs unfairly targets minorities. You may be in favor of it because you think it’s up to you, not the government, to decide what substances you’d like to consume as long as you don’t harm others. Or you may be sympathetic to the ballot measure based on the testimonials of patients with cancer or AIDS who swear that medical marijuana helps them cope with their illness.

But if pot is made legal, what would that mean for public health in the Golden State? Nothing good, says Keith Humphreys, a professor of psychiatry and behavioral medicine at the Stanford School of Medicine.

Humphreys, a clinical psychologist who recently spent a year in the Obama administration’s Office of National Drug Control Policy as a senior policy advisor, says the health effects of Proposition 19 are being overlooked by the 52% of Californians who supported the measure in a recent poll. In a podcast available on the Stanford website, he says his No. 1 fear is that it would create a lucrative product line for tobacco companies or create an industry that would stand “shoulder to shoulder with them lobbying against every anti-smoking restriction and expansion of public health and every taxation initiative.”

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Cigarettes still kill 400,000 people each year despite decades of regulation and anti-smoking campaigns, Humphreys said. But there’s reason to fear that Proposition 19 could make things worse. In European countries like the Netherlands, tobacco and marijuana are often smoked together and the combination is “both more addictive and more cancer-producing than either of those separately,” he said.

Humphreys said he has no doubt that marijuana has legitimate medical uses, and compounds within the plant will probably be turned into “maybe half a dozen decent medications” to alleviate pain, improve appetite and treat muscle spasms for patients with multiple sclerosis. But that doesn’t mean consumption of the entire plant — which contains more than 200 chemicals — is either beneficial or safe, especially when smoked, he said.

“Cocaine has medical uses,” especially as an anesthetic, Humphreys said, but that doesn’t mean it “should be available at 7-Eleven.”

You can download the complete podcast here.

By Karen Kaplan. Source.

June 8, 2010 – Hartford, CT—Subjects exhibit virtually identical psychomotor skills on a battery of driving simulator tests prior to and shortly after smoking marijuana, according to clinical trial data published in the March issue of the Journal of Psychoactive Drugs.

Investigators from Hartford Hospital in Connecticut and the University of Iowa Carver College of Medicine assessed the simulated driving performance of 85 subjects in a double-blind, placebo controlled trial. Volunteers responded to various simulated events associated with automobile crash risk — such as avoiding a driver who was entering an intersection illegally, deciding to stop or go through a changing traffic light, responding to the presence of emergency vehicles, avoiding colliding with a dog who entered into traffic, and maintaining safe driving during a secondary (in-the-car) auditory distraction. Subjects performed the tests sober and then again 30 minutes after smoking a single marijuana cigarette containing either 2.9 percent THC or zero THC (placebo).

Investigators reported that volunteers performed virtually the same after smoking cannabis as they did sober and/or after consuming a placebo. “No differences were found during the baseline driving segment (and the) collision avoidance scenarios,” authors reported.

Investigators did note, “Participants receiving active marijuana decreased their speed more so than those receiving placebo cigarette during (the) distracted section of the drive.” Authors hypothesized that subjects’ reduction in speed on this task suggested that they may have been compensating for perceived impairment. “[N]o other changes in driving performance were found,” researchers concluded.

A 2008 driving simulator study published in the scientific journal Accident, Analysis and Prevention also reported that drivers administered cannabis are likely to decrease their driving speed. “Average speed was the most sensitive driving performance variable affected by both THC and alcohol but with an opposite effect,” investigators reported. “Smoking THC cigarettes caused drivers to drive slower in a dose-dependent manner, while alcohol caused drivers to drive significantly faster than in ‘control’ conditions.’”

Previous reviews assessing the crash culpability risk of drivers under the influence of cannabis have reported a positive association between recent marijuana exposure (as typically measured by the presence of active THC in the driver’s blood) and a gradually increased, dose-dependent risk of vehicle accident. However, these studies have consistently found that this elevated risk is below the risk presented by drivers who have consumed legal quantities of alcohol. By contrast, studies have also reported that drivers engaged in the simultaneous use of both cannabis and alcohol can increase their risk of accident compared to the consumption of either substance alone.

NORML’s white paper assessing the impact of marijuana on psychomotor skills, “Cannabis and Driving: A Scientific and Rational Review,” is available online here. Source.