A bad case of deja vu...

There are two problems with the idea that smoking cannabis may prime the
brain for dependence on harder drugs (see This Week, p4).

Number one: there is no direct evidence. Number two: if cannabis does
behave this way, then by the researchers' own logic one would expect
alcohol and nicotine to do the same, for all three drugs push the same
dopamine button in the brain by very similar chemical mechanisms. Nobody,
however, is saying that beer and cigarettes turn people into potential
junkies and crackheads.

Perhaps this is because people don't buy these drugs from pushers with a
supply of harder substances. If so, the researchers should make it clear
that the link they are suggesting has a social as well as a biological
component. Otherwise, it is hard to disagree with cynics who might say that
cannabis is being singled out in these studies.

More puzzling is why the two teams have decided to float their "brain
priming" idea now when there are relatively simple experiments that could
be done to test it. If the researchers are right, then lab rats that have
been exposed to cannabis should become hooked on other drugs, particularly
heroin, more easily than rats that have never experienced the evil weed.

We eagerly await the results of this experiment but will not be placing any
bets. A quarter of a century ago, researchers claimed that cannabis rotted
the brain and reduced the sperm count. Neither finding was ever replicated.
Nobody is saying cannabis is safe, but it is hard to escape the feeling
that we've been here before.

The following sites offer a variety of information about the medicinal use
of marijuana:

[American] National NORML (National Organization for the Reform of
Marijuana Laws) Home Page: About Medicinal Marijuana
Medical Marijuana Research from the Multidisciplinary Association For
Psychedelic Studies (MAPS)
documents about Marijuana Research from Drug Watch International
Marijuana: Advances in Research (an antidrug site)
Medical Marijuana from HempNet
[American] National Institute on Drug Abuse (NIDA)

From New Scientist, 5 July 1997