No easy answers in study of legal marijuana's impact on alcohol use

December 29, 2015 by Deborah Bach
Credit: Alex Ranaldi / Flickr

Does legal marijuana tempt pot users to consume more alcohol—or are they likely to opt for cannabis instead of chardonnay?

A University of Washington team of researchers sought to address those questions in the context of evolving policies in the United States. Their findings, published online Dec. 21 in the journal Alcoholism: Clinical & Experimental Research, highlight the difficulties of gauging the impact of a formerly illicit drug as it moves into the mainstream.

Recreational marijuana use is now legal in four states and medical marijuana in 23 states. Research on legalization policies has focused largely on how they impact marijuana access and use. But the UW team wanted to know how legalization affects the use of , by far the nation's most popular drug.

The majority of adults in the U.S. imbibe to varying degrees, and alcohol abuse is the third leading preventable cause of death nationwide. Drinking accounts for almost one-third of driving fatalities annually, and excessive alcohol use cost $223.5 billion in 2006 alone.

"We chose to focus on alcohol because even relatively small changes in alcohol consumption could have profound implications for public health, safety and related costs," said lead author Katarína Guttmannová, a researcher in the UW's Social Development Research Group.

The researchers sought to determine whether legalizing marijuana led to it becoming a substitute for alcohol or tended to increase consumption of both substances. If it was the former, they reasoned, that could greatly reduce the costs of healthcare, traffic accidents and lower workplace productivity related to excessive drinking.

But if legalized marijuana resulted in increased use of both drugs, costs to society could increase dramatically, particularly since those who use both substances tend to use them at the same time. Those who use both substances simultaneously are twice as likely to drive drunk and face social troubles such as drunken brawls and relationship problems, a recent study found.

Drawing on previous studies, the researchers hypothesized that legalization of marijuana could result in either substitution or complementary effects. Marijuana and alcohol both provide users with similar "reward and sedation" effects, the researchers noted, which could prompt users to substitute one for the other. But blood levels of THC, the chemical responsible for most of marijuana's pleasurable psychological effects, increase with simultaneous alcohol use—so the quest for a better high might lead people to use both substances.

The researchers reviewed more than 750 studies on marijuana and alcohol use and focused on 15 that specifically addressed the links between marijuana policies and drinking. They looked at how decriminalized marijuana, medical marijuana and recreational marijuana impacted alcohol use.

The findings of those studies fluctuated widely, depending on the demographic and the type and frequency of alcohol and marijuana use. One study, for example, found that states where marijuana is decriminalized had more emergency room visits related to marijuana and fewer visits linked to alcohol and other drugs. Some studies found that high school seniors in states where pot was decriminalized tended to drink less, while other research found that college students who used pot also drank more.

Findings around medical marijuana also varied. One study reported that states with medical marijuana dispensaries had higher rates of both marijuana and alcohol use, as well as higher admissions into alcohol treatment facilities. But while states with medical marijuana had fewer alcohol-related fatalities overall, those with dispensaries saw more of those deaths.

Other research found that while legalized wasn't associated with any increases in underage drinking, it was linked with more binge drinking and simultaneous use of pot and alcohol among adults.

The issue is particularly complicated in Washington state, which legalized recreational marijuana use in 2012 after privatizing liquor sales the previous year. As a result, the uptick in alcohol sales made it difficult to isolate the impacts of legalized marijuana on drinking from the change in alcohol policy.

The researchers concluded that there's evidence of marijuana and alcohol being both substitutes and complements. Given the rapidly evolving landscape of marijuana policy, they say further study will be important to understand how changes in marijuana laws impact the use of alcohol and other drugs.

In particular, Guttmannová said, future studies should address specific dimensions of marijuana policies, timing of policy change and implementation, and different aspects of marijuana and alcohol use, such as age of users and whether they are episodic or regular consumers.

"This is a complicated issue and requires a nuanced approach," she said. "We were hoping to have more clear-cut answers at the end of our research. But you know what? This is the science of human behavior, and it's messy, and that's OK."

Explore further: Marijuana use more than doubles from 2001 to 2013; increase in use disorders too

More information: Alcoholism: Clinical & Experimental Research,

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4 / 5 (2) Dec 29, 2015
I don't follow the reasoning here. If you want to study the effects of legalizing marijuana, why confuse the issue by lumping it together with alcohol use? They both have detrimental societal effects. Is this study being done by casual marijuana smokers, perhaps looking for some small net societal benefit by possibly replacing alcohol? Otherwise, I don't get it. When you make it easier to access a drug that impairs judgment and response time, you are very likely to see an increase in incidents (and accidents) caused by impaired judgment and response time.

Measuring the effects of legalizing marijuana on automobile accidents should be pretty straightforward. This would be helpful to know before more states legalize a substance that may contribute to an increase in accidents.
1 / 5 (1) Dec 29, 2015
A literature review is not a study. This site is always biased towards prohibition, too. As to the interaction, Anheuser-Busch has voted with their wallets for years and it's obvious they think weed use decreases drinking. lol Maybe it just leads people to buy decent beer.

Hey, Nanny State akser, if you're so hep on public safety how about taking it in order, starting with what causes the most accidents/morbidity/mortality? Start with sleep. Employers can't mention a person's race, have to tip-toe when giving feedback so they don't hurt their feelings...but they can give them hours that destroy their sleep cycle! How many accidents does that cause? What about all the morbidity associated with non-reducing sugars consumption?

No, you're like most of the lot. "Responsible social policy" means "outlawing and scapegoating what I don't do".
not rated yet Dec 29, 2015
About the only people that might drink more booze when high is probably college students and they are a statistical class of their own that doesn't apply to the rest of the population and never will.

Most other people don't really mix the two or drink very little when smoking.

No I don't have links... I'm going by 40 years of experience knowing people that smoke weed and/or drink.
5 / 5 (1) Jan 01, 2016
Wine and weed complement each other very nicely. The key, of course, is moderation. There's nothing nastier than a drunken high-- bad form and a disaster about to happen.
4 / 5 (1) Jan 02, 2016
Everything is better with a bag of weed.

5 / 5 (1) Jan 02, 2016
I guess personal freedom doesn't come into play any more.

Live and Let Live.

As responsible adults we are capable of making lawful decisions, I don't NEED big brother or sister telling me how to live my life.

5 / 5 (1) Jan 02, 2016
No easy answers in study of legal marijuana's impact on alcohol use
There are no easy answers in any study of alcohol use.

I have a brother who lost a leg just below the knee because of chronic use. And not even that has had an impact. There are only three things that do have much of an impact, as anyone remotely familiar with the subject knows: jails, institutions, or death.
5 / 5 (1) Jan 03, 2016
" If you want to study the effects of legalizing marijuana, why confuse the issue by lumping it together with alcohol use? "

Because one of the arguments for legalization is the claim that it subsitutes alcohol use, and a claim against is that it adds on top of alcohol use and in combination produces greater harm.

What's easily observable by anyone in practice, people do tend to use both when both are available. Weed during the week - because it doesn't give you a hangover next morning - alcohol on the weekend. The net effect seems to be that people spend much more time intoxicated than they spent before with alcohol alone, and they also "treat" hangovers with weed because it takes the nausea away.
5 / 5 (1) Jan 03, 2016
"As responsible adults we are capable of making lawful decisions, I don't NEED big brother or sister telling me how to live my life."

As responsible adults we understand that there are also limits to our personal abilities, that we are not omnisciently wise in all our decisions, and that we can be subject to intellectual biases and other effects such as chemical or psychological addicitions that are out of our voluntary control.

That is why we voluntarily place a measure of trust and responsibility into the authorities we create for ourselves.

not rated yet Jan 19, 2016
I read on this site about a study that said virtually any amount of alcohol imbibed 10 minutes prior to smoking pot increased the absorption of THC. After that I had to try this out, for science, and it seems to work. If you want a better high, that isn't detracted by drunken sleepiness or sloppiness, stick to one shot just a while before you smoke, and then stick to smoking after. You can drink again after about an hour and repeat the process to maintain. Unless you're a super lightweight you won't get physically drunk.

Never drink a lot and then go smoke. This will cause what I term, an immediate spin-out. Nausea, Vomiting, loss of mental control in general, all sorts of bad things happen.

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