By Paul Armentano
18 May 2010
One of the indirect though no less serious consequences of marijuana prohibition is the mischaracterization of clinical research in order to support the federal government’s bankrupt policy.
For example, last week the Obama administration called for the expansion of states to enact laws criminalizing motorists who drive with the residual presence of drug or inactive drug metabolites in their body. In the case of marijuana, these policies are especially egregious because its metabolites may remain present in urine for weeks or months after past use. Further, studies have consistently reported that the presence of marijuana metabolites is not associated with psychomotor impairment or an elevated risk of motor accident — a result that should be self-evident given that cannabis metabolites only form in urine after the drug’s primary psychoactive compound, THC, has been broken down and converted by the body over a period of several hours.
So how does the federal government justify its call for implementing such an inane and discriminatory policy? Simple. By claiming that supposed ‘marijuana and driving menace’ is so prevalent and severe that lawmakers have no other choice but to enact such inflexible and nonsensical policies to halt it.
Now I’ve written on the subject of cannabis use and psychomotor performance numerous times, including recently authoring the white paper Cannabis and Driving: A Scientific and Rational Review. In short the science says this: there appears to be a positive association between very recent cannabis exposure and a gradually increased risk of vehicle accident; however, this elevated risk is below the risk presented by drivers who have consumed even small (read ‘legal’) quantities of alcohol.
Does this conclusion support the blanket criminalization of marijuana or the enactment of the sort of zero-tolerant per se driving laws outlined above? No more so than such a conclusion advocates for a return to alcohol prohibition.
So what’s the administration to do? That’s easy — just fund more research. And what to do when that federally funded research fails to produce the results they were looking for? That’s even easier: just claim that they do anyway.
Such is the case with a just-published study in the Journal of Psychoactive Drugs assessing the psychomotor skills of subjects on a battery of off-road driving simulator tests both before and after smoking marijuana (and/or placebo).
During the course study, subjects were asked to respond 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 changing traffic lights, responding to the presence of emergency vehicles, avoiding colliding a dog who entered into traffic, and maintaining safe driving during a secondary (in-the-car) auditory distraction. Subjects performed these tests sober, and then shortly (30 minutes) after smoking a single marijuana cigarettes (or placebo).
So how did the subjects perform? Much to the apparent chagrin of the investigators, just fine.
“No sex differences or interactions of sex and marijuana were observed for any of the driving tasks. Participants receiving active marijuana decreased their speed more so than those receiving the placebo cigarette during a distracted section of the drive. An overall effect of marijuana was seen for the mean speed during the distracted driving (PASAT section). [N]o other changes in driving performance were found.”
In short, subjects had no greater likelihood of responding adversely to any of the simulated events after smoking marijuana than they had prior to consuming cannabis.
Of course, these are not the sort of results that NIDA — who provided funding for the study — or the Drug Czar’s office are looking for. Therefore, the authors are required find some outcome — any outcome — supporting the administration’s claim that driving under the influence of cannabis is a serious and significant threat. How do they do that in this case? Simple; by stating subjects lack of impairment was, in fact, implicit evidence of their impairment!
“Persons smoking the placebo cigarette showed an improvement in performance of the PASAT during the driving task, likely attributable to practice effects. Under the influence of marijuana, however, no differences were found between PASAT performance during practice testing and while driving. Participants who smoked active marijuana decreased their speed during this section of the drive, suggesting additional compensatory skills were used.”
In other words, the authors are claiming that because subjects on one specific test (the auditory distraction test) drove more slowly when completing the task after smoking marijuana than they did prior to consuming cannabis, but otherwise manifested no difference in the outcome of said test — or on any other test for that matter — that this is somehow strong evidence that marijuana has a significant and adverse impact on driving.
SUMMARY AND CONCLUSIONS
Under the influence of active marijuana, participants exhibited increased drowsiness, although this did not appear to affect their driving [emphasis mine]. Participants under the influence of marijuana failed to benefit from prior experience on a distracter task [what the authors want the reader to emphasize] as evidenced by a decrease in speed and a failure to show expected practice effects. This study supports the existing literature that marijuana does affect simulated driving performance [ditto], particularly on complex tasks such as divided attention. It is anticipated that many teenagers and young adults driving under the influence of marijuana are doing so while conversing with friends in the car, listening to music, talking on the cell phone and/or text messaging others. These behaviors divide the driver’s attention and are particularly dangerous under the influence of marijuana [what the authors really, really want the reader to emphasize].”
And that, my friends, is just the latest example of how marijuana prohibition corrupts, and how absolute marijuana prohibition corrupts absolutely.
Paul Armentano is the Deputy Director of NORML and the NORML Foundation.