Marijuana Memory Loss Tied to Cannabis Composition

When it comes to causing short-term memory loss, a new study finds that not all strains of marijuana are created equal.

A study published in the British Journal of Psychiatry, says it all depends upon the strain of cannabis someone smokes - the ratio of two chemicals in particular: Tetrahydrocannabinol, or THC, and cannabidiol. Nature News, which reported the findings, noted that "THC is the primary active ingredient," associated with effects associated with euphoric or giddy highs (as well as feelings of anxiety or paranoia.) "The second chemical, cannabidiol, has more calming effects, and brain-imaging studies have shown that it can block the psychosis-inducing effects of THC2. Skunk-type strains of cannabis contain a higher ratio of THC to cannabidiol than do hashish or herbal types."

The implicit message to pot smokers concerned about memory loss: choose strains with higher concentrations of cannabidiol, Valerie Curran, a psychopharmacologist from University College London who led the study, tested marijuana samples smoked by 134 volunteers for the levels of THC and cannabidiol they contained.

"Analysis showed that participants who had smoked cannabis low in cannabidiol were significantly worse at recalling text than they were when not intoxicated. Those who smoked cannabis high in cannabidiol showed no such impairment. The results suggest that cannabidiol can mitigate THC's interference with memory formation."