Do Rx Opioids Really Increase Risk of Fatal Accidents?

By Pat Anson, PNN Editor

A recent study published in JAMA Network Open made headlines when it claimed that use of prescription opioids more than doubled the risk of causing a fatal car accident.  

Researchers at Columbia University Mailman School of Public Health looked at death certificates and toxicology tests on drivers involved in over 18,000 fatal two-vehicle accidents from 1993 to 2016. They found that 1,467 of the “crash initiators” tested positive for hydrocodone, morphine, oxycodone or other prescription opioids.    

The researchers reported their findings as “compelling evidence that use of prescription opioids by drivers is a significant contributing factor” in fatal crashes, which was a dog whistle for media outlets like CNN to warn, “Opioid epidemic spilling over onto roads.”

It turns out the evidence was not so compelling after all.

Like many states, Maryland faces growing rates of opioid abuse and addiction. But when researchers looked at opioid-related crashes in Maryland from 2006 to 2017, they found no significant increase in fatal accidents.

“The fact that opioid crashes in Maryland over the last 10 years have been more or less steady was a surprise,” Johnathon Ehsani, PhD, a professor at the Johns Hopkins Bloomberg School of Public Health told The Washington Post.


That is striking, because Maryland is one of those states that has been quite severely affected by the overall opioid epidemic.”

Ehsani and his colleagues took another look at the toxicology data and realized it was misleading. The reason was simple: Because hospitals and first responders often give opioid medication to patients injured in accidents, autopsies will detect those opioids in patients who later die from their injuries. In other words, the drivers may not have been under the influence of opioids before the crash.

When researchers only looked at a sub-sample of drivers who died at the scene, they found that the use of prescription opioids was “considerably lower than those who died hours or days following the crash.”

“We applied a stricter definition than our other colleagues did,” said Ehsani, who published his findings in the less prominent journal Accident Analysis & Prevention. “We were more conservative in our case definition.”

The JAMA study apparently over-counted the number of opioid-related crashes by not differentiating between drivers who died at the scene and those who died after getting medical treatment with opioids.

"When determining the prevalence of opioid use in a population, it can be tricky to untangle the two circumstances," says Ehsani. "Thinking differently about the way in which researchers count cases has implications that can offer policymakers and public health professionals more meaningful results."

No one is suggesting that it’s okay to drive a vehicle while impaired by opioids. But it’s also not okay for researchers and prominent medical journals to use flawed data to suggest that patients using prescription opioids are more likely to cause fatal accidents.

In Maryland, they found just the opposite may be true.

“It could be that a number of people who are impaired by opioids choose not to drive,” Ehsani said. “It could be that there is some self-selection going on in that population or it could be that some of those who are most seriously impaired are unable to or don’t have access to a vehicle to drive.”

‘Cannabis Tourism’ Linked to More Fatal Accidents

By Pat Anson, PNN Editor

Has marijuana legalization made driving more dangerous?  There have been conflicting claims over the years that states where cannabis is legal have more car crashes. And one recent study found that over half of medical cannabis users drive while impaired.

A new study adds a little more clarity to the issue.

Researchers at Monash University in Australia looked at traffic fatalities in three U.S. states where recreational cannabis was legalized (Colorado, Washington and Oregon), and in eight neighboring states and British Columbia.

They found there was an average of one additional traffic fatality for every million residents. That may not sound like much, but when you consider there were 27 million people in the affected areas, it adds up to 170 additional deaths in the first six months after legalization.

Many of the additional deaths were attributed to “cannabis tourism” in which people in neighboring states and provinces purchased recreational cannabis in legalized states and then drove home while under the influence.


"The results suggest that legalizing the sale of cannabis for recreational use can lead to a temporary increase in traffic fatalities in legalizing states. This spills over into neighboring jurisdictions through cross-border sales, trafficking, or cannabis tourists driving back to their state of residence while impaired,” says lead author Tyler Lane, PhD, a postdoctoral research Fellow at Monash.

"Our findings suggest that policymakers should consult with neighboring jurisdictions when liberalizing cannabis policy to mitigate any deleterious effects."

Because the increase in fatalities was temporary, Lane believes it could be due to an initial “celebratory response to legalization” that contributes to cannabis tourism. His study was published in the journal Addiction.

Fatalities Drop in Medical Cannabis States

While fatalities rose in states with recreational cannabis, Lane notes that previous research has found a decrease in traffic fatalities in states that legalized medical marijuana. That may be because patients may be substituting cannabis for alcohol and other controlled substances used to relieve symptoms.

“There seem to be differences between medicinal and recreational user consumption patterns. Medicinal users have a tendency to substitute, but recreational users are more likely to treat alcohol and cannabis as complements and use them together,” Lane said in an email to PNN. 

“Because marijuana on its own is less impairing than alcohol, and combined used is much more impairing than either in isolation, it suggests that when people substitute alcohol for cannabis (in the medicinal use context), they will still be impaired, but to a much lower degree than if they were still using alcohol.” 

This “harm reduction role” of medical cannabis was noted in a 2016 Canadian study that found patients reduced their use of alcohol, illicit drugs and prescription drugs when cannabis was taken for medical reasons. 

Medical marijuana is currently legal in 33 states and Washington DC, and ten states allow its recreational use.

Is Medical Marijuana Causing More Fatal Crashes?

By Rochelle Odell, Columnist

Medical marijuana’s role in fatal auto accidents is a subject that’s rarely addressed by those who support full legalization of cannabis. But I found numerous articles about it online and all show there is cause for concern.

An NBC News story warned that “Pot Fuels Surge in Drugged Driving Deaths” back in 2014, the year after Colorado became the first state to legalize recreational marijuana:

“During each shift at her drive-through window, once an hour, Cordelia Cordova sees people rolling joints in their cars. Some blow smoke in her face and smile.

Cordova, who lost a 23-year-old niece and her 1-month-old son to a driver who admitted he smoked pot that day, never smiles back. She thinks legal marijuana in Colorado, where she works, is making the problem of drugged driving worse.”

“Drugged driving” is a term I had not heard before. Police agencies and medical professionals usually refer to it as driving under the influence or operating a vehicle while intoxicated. It is a perfect description, not only for marijuana, but for any substance that alters your ability to safely operate a vehicle.


The NBC News story quotes researchers at Columbia University, who looked at toxicology reports on over 23,000 dead drivers in six states were medical marijuana was legal. Cannabis was detected in the bodies three times more often in 2010 than in 1999.  

"This trend suggests that marijuana is playing an increased role in fatal crashes, said Dr. Guohua Li, co-author and director for Injury Epidemiology and Prevention at Columbia University Medical Center.

But alcohol was the most common mind-altering substance detected, appearing in the blood of nearly 40 percent of the drivers who died in 2010.

Research on this subject can be somewhat contradictory. A second study at Columbia found that states with medical marijuana laws had an 11 percent decrease in traffic fatalities. They also found there were fewer alcohol related accidents, suggesting that some younger drivers were substituting marijuana for alcohol.

Marijuana, like opiates and alcohol, should never be consumed by someone intending to drive. Even cannabidiol (CBD) based medications, which marijuana supporters tout as safe, may contain trace amounts tetrahydrocannabinol (THC), the chemical ingredient in cannabis that makes people high.

I am not an active proponent of medical marijuana, although I realize there are those who benefit from its use. But cannabis is not always the "magic bullet" when it comes to pain relief, and not all pain patients support it.

I tried CBD medication for three weeks and it did nothing for my pain. Being asthmatic precludes me from smoking or vaping, and I have been told using edibles in the amount required to achieve pain relief would require a large amount. Medical marijuana is also costly and can be cost prohibitive for those of us on fixed incomes.

I did vote for full legalization last year when it was on the California ballot. I also believe those who buy it from medical marijuana dispensaries have a right to know where it is cultivated, along with what pesticides, fertilizers or other harmful substances may have been used in its cultivation. People are going to use marijuana whether it is legal or illegal, so state and federal governments should legislate accordingly.

Studies show that Colorado, Oregon and Washington State have all seen an increase in car crashes since they fully legalized marijuana, although the number of fatal crashes has remained about the same. A recent analysis by the Denver Post found the number of drivers in Colorado who tested positive for marijuana after fatal crashes has risen by 145 percent since 2013.

Like everything else, we can draw our own conclusions from these statistics. I only ask that readers who are medical marijuana users check your state’s laws before smoking or vaping, consuming CBD, or ingesting the popular edibles.

THC is a known psychoactive and can affect your ability to safely operate a vehicle. CBD can also show up in toxicology reports and will reflect on the driver if they’re involved in an accident. Please educate yourself and be sober from any substance, legal or illegal, before driving.

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Rochelle Odell lives in California. She’s lived for nearly 25 years with Complex Regional Pain Syndrome (CRPS/RSD).

The information in this column should not be considered as professional medical advice, diagnosis or treatment. It is for informational purposes only and represents the author’s opinions alone. It does not inherently express or reflect the views, opinions and/or positions of Pain News Network.