As more and more states in the United States legalize marijuana for recreational use, it's not uncommon to see people smoking a joint or taking an edible while drinking a beer or a glass of wine. But what happens when you mix marijuana and alcohol? Is it safe? Is it fun?
Scott Lukas, a professor at Harvard Medical School, led a 2011 study that is among the few to investigate what happens in the brain while cross-faded and came to some surprising conclusions. It's safe to say that drinking, followed by smoking increases the effects of both drugs and, in some cases, can cause unpleasant adverse reactions.
What happens if you drink alcohol and smoke weed at the same time?
First off, it's important to note that marijuana (or THC to be more specific) and alcohol are two psychoactive substances that are far from being similar to one another. THC, the main psychoactive substance found in cannabis, acts upon the brain's cannabinoid receptors triggering its signature high, along with side effects like paranoia, a distorted sense of time, attention deficit, and more. Alcohol, on the other hand, depresses the nervous system with significant consequences to motor skills - walking in a straight line can be an arduous quest while in a drunken haze.
So, one might think that if you smoke and drink at the same time, the two effects will combine. But neurochemistry is far more complicated than adding left and right together. Lukas found that not only did the two effects combine, but in some instances, the effects considerably became amplified. For instance, Lukas noticed that subjects who smoked a joint and also drank a lot of alcohol (a couple of shots) had twice as much THC in their blood than those who didn't drink at all. Oddly, this seems to happen only when you drink first, and then smoke, but not the other way around.
The explanation has to do with the fact that alcohol opens up blood vessels in the gastrointestinal tract helping the THC to be absorbed more efficiently.
Also, those who smoked and consumed alcohol self-reported that the high was triggered much sooner and rated their high as 'better', but only to a point. If you drink too much before lighting the first joint, you risk getting 'greened out'. That is, suffering from nausea, bouts of vomiting, and an intense urge to lie down. Alcohol poisoning can be life-threatening and should never be taken lightly.
Oddly enough, in a second study run by Lukas and colleagues, the researchers found smoking first followed by drinking results in less alcohol in the bloodstream. THC seems to alter the motility of the gastrointestinal tract in such a way that it lowers alcohol levels. But this delay in the sensation of being drunk may prompt people to consume more alcohol than they would have done otherwise.
While all this may sound like mixing the two at moderate levels can make for a more pleasurable experience, it's important to note that combining alcohol and marijuana enhances not only the high but also the lows. Impaired judgment and increased heart rate - common symptoms while high on weed - become much more intense. A 2010 study found that heavy marijuana users who got reasonably intoxicated with alcohol and then smoked a joint containing THC suffered impairments to critical tracking, divided attention, and stop-signal performance that were greater than those by alcohol alone.
It's also worth noting that marijuana has an antiemetic effect, meaning it makes it harder for the body to vomit. As you may know, vomiting is the body's first line of defense against severe alcohol intoxication. In extreme cases, a user might choke on the vomit and die.
Combining weed and alcohol could also be potentially dangerous for people with heart problems and also increases the risk of accidents due to the enhancer motor impairment compared to individual use of either drug. Researchers from the Boston Medical Center and the University of Victoria found that people who died in crashes involving cannabis had 50% greater odds of also having alcohol in their system.
Bottom line: mixing alcohol and marijuana is common, but the combination can be quite dangerous if a user doesn't do it in moderation. It's best to stick to just one of the two.