Marijuana “Submarines” Work, but only if the Passive Smoker Is Willing

A group of researchers at the Johns Hopkins University (Maryland, USA) has studied the veracity of theories claiming that a passive marijuana smoker can experience actual effects stemming from cannabis's psychoactivity.

With their research ('Non-smoker exposure to second-hand cannabis smoke II: Effect of room ventilation on the physiological, subjective, and behavioural/cognitive effects'), the experts also sought to analyse how a poorly ventilated room impacts these effects. To this end they assembled six regular smokers and six non-smokers in a special compartment, the size of a small room they themselves made, and subjected them to several blood tests to confirm that they had not smoked prior to the test.

The scientists then gave 10 joints to each smoker to freely smoke in the room, which was completely sealed for 60 minutes. The researchers repeated the same session, this time with ventilation, to verify the difference in the effects. The result was positive: those who underwent the test in the sealed room, even though they had not smoked cannabis directly, experienced the effects of the plant's consumption. Those who had undergone the test with ventilation also experienced certain effects, but they were much slighter (and almost imperceptible) than those detected in the other group.

In conclusion, these researchers were able to verify that passive marijuana smokers are affected by the plant's effects in a closed space, even when they do not smoke directly. The study suggested, however, that passive smokers must be willing in order for those effects to be significant.