Can You Really Get A Secondhand High?

Photographed by Rachel Cabitt.

Sometimes just walking into a hazy dorm room can make you feel a little high, way before anyone even offers you a hit. And if you hang around at enough concerts, at some point you're bound to wonder if you're somehow a bit high as you leave a show. But can you really get stoned just from being around someone else who's smoking?

According to anecdotal evidence, the answer is something like, "Absolutely, yes, it happens all the time." After all, shotgunning weed — taking a huge hit, inhaling a bit, and then exhaling into your partner's mouth — is a popular move among couples. So we know it is definitely possible to get high without smoking directly. But whether or not it can happen unintentionally is a different story.

Research suggests it's a far rarer occurrence than the internet would have you believe. After inhaling and holding cannabis smoke in your lungs for a few seconds, you only exhale a tiny amount of THC, the major psychoactive compound in weed, Cecilia J. Hillard, PhD, a researcher at the Medical College of Wisconsin, tells Business Insider. So even if you inhale some secondhand smoke, it'll take a lot for you to actually feel high. And, in most real-world scenarios, research shows that walking through a cloud of pot smoke isn't going to do do much to you.

That said, a recent pair of studies in the journal Drug and Alcohol Dependence and the Journal of Analytical Toxicology from a group of researchers at Johns Hopkins University confirmed that — in extreme circumstances — contact highs are definitely real. How extreme must the circumstances be? Well, in an experiment the researchers referred to as "almost a worst-case scenario," they gave six smokers 10 potent "cannabis cigarettes" to consume over the course of an hour. But another six non-smokers were also in the 10-foot-by-13-foot room with them — oh, and in one experiment, the ventilation was switched off.

After an hour in this smoky box, the non-smokers reported feeling "pleasant," sleepy, and hungry. They also performed more poorly on a test of their response time. But neither their blood nor their urine showed a significant increase in THC.

So, sure, if you're at a concert and everyone around you is lighting up, you may feel a bit buzzed. But you won't get to the same level of high you would if you were inhaling yourself. That also means that you're probably not going to fail a drug test based on a contact high. And, no, you're not getting high just because you smell a bit of weed wafting down the hall. But if you're concerned about getting a contact high, you can always encourage your buds to partake in non-smokable forms of cannabis.

Refinery29 in no way encourages illegal activity and would like to remind its readers that marijuana usage continues to be an offense under Federal Law, regardless of state marijuana laws.