Smoking marijuana leads consumers to experience a sense of mild euphoria and relaxation, often referred to as the "high." Throughout the past, pop culture has greatly contributed to the stigmatization of the plant, including further perpetuating the concept of the "contact high." Anecdotal evidence often supports the theory, with some confirming that in their experiences, being around someone smoking marijuana was enough for them to feel the euphoric side effects regardless of whether that was their intention or not.
When taking a closer (and scientific) look at the elusive idea that you can experience a high from secondhand marijuana smoke, it is important to consider a variety of factors, including the fact that everyone has a unique relationship and reaction to marijuana due to our individualized endocannabinoid systems. Other factors such as environment, amount of exposure and duration of time also could influence the tangibility of the contact high, as does an individual's belief system. In other words, due to the social setting and one's general outlook of marijuana, being around enough passive smoke could yield a similar
In other words, due to the social setting and one's general outlook of marijuana, being around enough passive smoke could yield a similar psychoactive response even if science shows it's likely just a psychological placebo effect.
Several studies have taken place over the years examining the probability of the contact high being a real thing or just the stuff of social fabrication. Research points to generally inclusive findings, while the internet remains relatively divisive on the subject. Reachers note that experiencing a high from inhaling passive smoke is only possible in extreme conditions and the overall likelihood of getting high from walking through a cloud of smoke is acutely slim to none.
A 2010 field study taking place in the Netherlands found that after monitoring non-smokers in a well-attended cannabis cafe for three hours, only trace amounts ofTHC were detected after passive exposure. Additionally, none of the participants would have failed a mandated urine drug test due to the amounts being too minuscule to signify a positive result.
In 2015, a field study examined the effects of secondhand smoke by way of putting participants in a 10-by-13-foot room, designed to mimic environments such as being in an unventilated room or enclosed vehicles. The study found that participants experienced a "mild sense of intoxication and mild impairment on measures of cognitive performance." In this study, which was conducted by researchers at Johns Hopkins, the participants in the non-ventilated room did not pass the equivalent of a workplace drug test, while the participants in the ventilated room did pass the drug test. This study in particular showcases how little residual THC is present in the exhaled air and that it depends a great deal on environmental factors such as ventilation.
The study found that participants experienced a "mild sense of intoxication and mild impairment on measures of cognitive performance."
Ultimately, more research is required to make a conclusive statement regarding the probability and actuality of experiencing a contact high. However, if you smell a bit of marijuana or are standing near someone smoking, there's no need to worry about any unwanted side effects, outside of possibly experiencing itchy eyes or runny noses from the smoke exposure. Unless the circumstances are extreme, the effects from being near secondhand marijuana smoke will be negligible.