By Robert Preidt
TUESDAY, May 19, 2015 (HealthDay News) -- In unventilated rooms or vehicles, secondhand marijuana smoke can affect people who aren't smoking the drug, a new study finds.
In those situations, nonsmokers can have "mild intoxication," memory and coordination problems and, in some cases, have a positive result for the drug in a urine test, the Johns Hopkins University School of Medicine team said.
"Many people are exposed to secondhand cannabis smoke," study lead author Evan Herrmann, a postdoctoral fellow in psychiatry and behavioral sciences, said in a Hopkins news release.
"The scenario we looked at was almost a worst-case scenario. It could happen in the real world, but it couldn't happen to someone without him or her being aware of it," Herrmann explained.
In the study, six marijuana smokers and six nonsmokers spent an hour side-by-side in a 10- by 13-foot room for two sessions. Each smoker was given 10 strong marijuana cigarettes to smoke. In one session, the room's ventilation fans were turned on. In the other session, the fans were turned off and the room filled with marijuana smoke.
When the fans were turned off, the researchers "found positive drug effects in the first few hours, a mild sense of intoxication and mild impairment on measures of cognitive [mental] performance," study senior author Ryan Vandrey, an associate professor of psychiatry and behavioral sciences, said in the news release.
"These were relatively slight effects, but even so, some participants did not pass the equivalent of a workplace drug test," he added.
The study was published online recently in the journal Drug and Alcohol Dependence.