Marijuana update

Alternet - Contrary to what you may have heard, the percentage of Americans reporting having experienced pot-related problems is declining. That’s according to the results of a newly published study in the journal JAMA Psychiatry.

Investigators at the Washington School of Medicine in St. Louis assessed trends in marijuana use and in the prevalence of marijuana use disorders during the years 2002 to 2013. Researchers found that the self-reported use of cannabis by adults increased an estimated 19 percent, but that reports of cannabis-related problems actually declined during this period.

Separate evaluations of self-reported marijuana use by young people have determined that rates of cannabis use by high-school students are significantly lower today than they were 15 years ago.


The study's findings contradict those of a widely publicized 2015 paper which alleged that the use of marijuana had doubled over the past decade and that an estimated one-third of those who consumed cannabis did so problematically. Predictably, while the 2015 study received widespread coverage, only a handful of media outlets have published follow up stories highlighting the revised data.

Stoned drivers are slower drivers. That is the finding of a just published federal study in the Journal of Applied Toxicology. Its conclusions mimic those reported in a series of on-road driving studies performed by the US National Highway Traffic Safety Administration in the 1990s.

Investigators affiliated with the US National Institute on Drug Abuse and the University of Iowa assessed the effects of vaporized cannabis on simulated driving performance. Researchers report that cannabis-positive subjects decreased their speed and increased the distance between their vehicle and the car in front of them, while alcohol-positive participants did the opposite.

While some studies have reported that THC-positive drivers possess a nearly two-fold risk of motor vehicle accident compared to drug-free drivers, other reviews have reported comparatively less risk and, in some cases, no elevated risk after adjusting for confounding variables such as age and gender. By contrast, driving with legal amounts of booze in one’s system is associated with a four-fold increased crash risk, while operating a motor vehicle with two or more passengers more than doubles one’s risk of a motor vehicle crash.

Longstanding claims that smoking pot leads to depression have been rejected in a new longitudinal study published in the Journal of Affective Disorders.

A team of Swedish investigators conducted a three-year prospective study in a cohort of 8,600 men between the ages of 20 and 64 to assess whether cannabis use was associated with increased incidences of depression later in life. After scientists adjusted for potentially confounding variables, such as other illicit drug use and family tension, they reported no link between pot use and symptoms of clinical depression or anxiety.

Investigators did find that subjects who reported suffering from depression during their baseline interviews were more likely to be pot smokers at follow up. However, these respondents were also more likely to consume other illicit drugs as well.

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