Memory and psychotic effects of smoking cannabis
Researchers at the University College London, in the UK, report on the acute negative effects of smoking pot.
Here are their results and why they’re important.
First, the details.
- 134 cannabis users were tested 7 days apart on measures of memory and psychotic symptoms.
- They were tested once while drug free and once while acutely intoxicated by their own chosen smoked cannabis.
- A sample of cannabis (as well as saliva) was collected from each user and analyzed for levels of cannabinoids — cannabidiol and delta 9-tetrahydrocannabinol (THC).
- These constituents of cannabis have opposing effects both pharmacologically and behaviorally.
- Street cannabis contains varying levels of each cannabinoid.
And, the results.
- Groups didn’t differ in the THC content of the cannabis they smoked.
- Those who smoked cannabis low in cannabidiol showed marked impairment in prose recall.
- Participants smoking cannabis high in cannabidiol showed no memory impairment.
- Cannabidiol content didn’t affect psychotic symptoms, which were elevated in both groups when intoxicated.
The bottom line?
The authors concluded, “The antagonistic effects of cannabidiol at the CB1 [cannabinoid] receptor are probably responsible for… attenuating the memory-impairing effects of THC.”
There’s a higher risk of memory impairment when smoking low-cannabidiol strains of cannabis like ‘skunk,’ which now dominates the street market. These strains increase the risk of cognitive harm.
Dr. Marilyn Huestis at the National Institutes of Health tells us why this study is important from a societal perspective.
- Cannabinoids are the number one illicit drug detected in motor vehicle injuries, fatalities, and driving under the influence of drugs cases.
- Critical skills needed for the safe operation of motor vehicles and other forms of transport can be impaired following cannabis use.
- Impaired functioning of psychomotor activities include coordination, tracking, and vigilance, as well as cognitive behavior — memory, learning, attention, information processing, decision-making, and perception.
10/2/10 16:19 JR
