Novel study of high-potency cannabis shows some memory effec
For the study, researchers observed cannabis users as they smoked high-potency cannabis flower or vaped concentrates.
The researchers found no impact on the users' performance on decision-making tests in comparison to a sober control group but did find some memory impairments related to free recall, source memory, and false memories.

The 80 participants were divided into four groups: two groups used cannabis flower with more than 20% THC but one containing cannabidiol (CBD), a non-psychoactive component of cannabis, and the other without CBD. Another group vaped cannabis concentrates with more than 60% THC that included CBD. A fourth group remained sober.

For all cannabis using groups, the researchers found no effect on a range of decision-making tests including risk perception and confidence in knowledge. On a few memory tests, there were also no significant differences between the cannabis-using and sober groups, including prospective memory. The cannabis-using participants also did well on temporal order memory, the ability to remember the sequence of previous events.

However, the groups that smoked cannabis flower with CBD did worse on verbal free recall trials. The groups that used cannabis without CBD and the group that used concentrates, performed worse on a measure of source memory which means being able to distinguish the way previously learned information was presented. Finally, all three cannabis-using groups did poorly on a false memory test.

High-potency cannabis flower with CBD impaired free recall, a high-potency flower without CBD and concentrates had detrimental effects on source memory, and all three products increased susceptibility to false memories. CBD did not offset impairments and concentrates were self-titrated producing comparable intoxication and impairment as a flower.

Scientific Reports