Cannabinoids and memory

Cannabinoids interfere with short term, ummmm…., now what was that word … whatever. Sometimes that’s good. Especially if you’re a birdbrain.

Smoking pot interferes with short-term memory. That’s the source of about half of marijuana-related humor (the other half being about the munchies).

In the 1980s, Raphael Mechoulam and his colleagues found that the brain makes its own cannabinoids (which they dubbed “anandamides,” from the Sanskrit word for “bliss”), and a set of neurons with anandamide receptor sites. That explains why pot-smoking is psychoactive. Still unexplained is the biological function of the anandamide system; presumably, the ability to get stoned wasn’t a survival advantage.

Even before anandamide ligand-receptor system was discovere, some people — notably Andrew Weil — had claimed that pot-smoking might have an offsetting benefit in enhancing creative imagination. As might be expected, the relevant studies, which might yield politically incorrect results, mostly haven’t been done.

A new study suggests that memory interference and creativity enhancement might be different results of a single underlying process. Memory, it seems, can interfere with imagination.

In the new study, birds were shown a worm in a wormhole. Then the lights were turned off and back on, and the birds were allowed to search for the worm. Birds given a drug that blocks the actions of the brain’s endogenous cannabinoids performed better on the task of finding the worm where it had been before, suggesting that the cannabinoid system worsened performance on short-term memory tasks.

That left the puzzle as to why the system was there in the first place. But a second experiment suggested an answer to that puzzle. If the location of the worm was changed while the lights were out, the cannabinoid-blocked birds stubbornly insisted on finding the worm where it used to be, while those with normal cannabinoid function were much quicker to try alternative locations.

You might say that the cannabinoid-enabled birds flip-flopped, while the cannabinoid-blocked birds stayed the course.

The paper (DeVoogd, T.J., et al., “Cannabinoid Inhibition Improves Memory in Food-storing Birds.” Proceedings of the Royal Society: Biological Sciences (Vol. 271, No. 1552, Oct. 7, 2004) doesn’t seem to be up yet on the Royal Society website. Cornell has posted a well-written press release, though.

Author: Mark Kleiman

Professor of Public Policy at the NYU Marron Institute for Urban Management and editor of the Journal of Drug Policy Analysis. Teaches about the methods of policy analysis about drug abuse control and crime control policy, working out the implications of two principles: that swift and certain sanctions don't have to be severe to be effective, and that well-designed threats usually don't have to be carried out. Books: Drugs and Drug Policy: What Everyone Needs to Know (with Jonathan Caulkins and Angela Hawken) When Brute Force Fails: How to Have Less Crime and Less Punishment (Princeton, 2009; named one of the "books of the year" by The Economist Against Excess: Drug Policy for Results (Basic, 1993) Marijuana: Costs of Abuse, Costs of Control (Greenwood, 1989) UCLA Homepage Curriculum Vitae Contact: