Vaping marijuana has a more intense impact than smoking the same amount, according to a small study by researchers at the Johns Hopkins Behavioral Pharmacology Research Unit.

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The research was funded by the Substance Abuse and Mental Health Services Administration, according to Live Science, and found that vaping the drug resulted in a much more powerful effect, regardless of the dosage of THC, the main psychoactive component of pot.

"Vaporized cannabis produced significantly greater subjective drug effects, cognitive and psychomotor impairment, and higher blood THC concentration than the same doses of smoked cannabis," the scientists said.

Compared to smoked cannabis, vaped marijuana in both low and high doses produced higher concentrations of THC in study participants' blood. Those vaping marijuana also made more mistakes on cognitive tests, researchers said.

"Notably, the highest dose of cannabis administered in this study is substantially smaller and has a lower THC concentration than what is typically contained in pre-rolled cannabis cigarettes available for purchase in cannabis dispensaries," researchers said.

Medical marijuana is now legal in 30 states and Washington, D.C., with recreational use legal in nine states and Canada. Researchers said more study is needed on the impact of new products and new means of delivering marijuana, like vaping.

The study was published last week in the journal JAMA Network Open.