Marijuana a major cause of accidents? What study says

(CBS) Studies have shown marijuana may help fight glaucoma, boost appetites in cancer patients, and reduce nausea, aches, and pains for some disease sufferers. But a new study links pot to something else:

Deadly car crashes.

PICTURES: Drugged driving: 20 states with highest rates

The study found that nearly 30 percent of fatally injured drivers tested positive for drugs other than alcohol, with marijuana being the main culprit.

"Given the ongoing epidemic of drug-impaired driving and the increased permissibility and accessibility of marijuana for medical use in the U.S., it is urgent that we better understand the role of marijuana in causing car accidents," study author Dr. Guohua Li, professor of epidemiology at Columbia University, said in a written statement.

For the study - published in the Oct. issue of Epidemiologic Reviews -researchers analyzed nine large-scale drugged driving studies. The researchers found that drivers who tested positive for marijuana within three hours of using were more than twice as likely to be involved in a motor vehicle crash. The study also showed that the crash risk was higher if the marijuana concentration levels found in the urine were higher.

So the more marijuana motorists smoke before getting behind the wheel, the more likely they are to crash? Stop the presses.

Some experts were weary of the study's findings.

"We can't really say yet that marijuana increases the risk by two or three times," Chuck Farmer, director of statistics at the Insurance Institute for Highway Safety in Arlington, Va., told HealthDay. "Most of their studies pointed to a very strong bad effect of marijuana on driving, but there are other studies out there that actually go the other way."

The study's authors suggested that marijuana use may worsen reaction and coordination abilities, but weren't sure whether the amount of marijuana used, or how it was ingested, contributed to the crash rates.

The findings have caused some highway safety advocates to sound the alarms, because pro-medical marijuana legislation has been passed in 16 states, with movements underway in several more states.

Jonathan Adkins, spokesperson for the Governors Highway Safety Association, told HealthDay:

"We see this as a national priority and are seeking a range of actions to address the problem comprehensively."

What do you think? Does drugged driving risk suggest that "medical marijuana" is a bad idea?

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