Cannabis and Cognitive Functioning by Nadia Solowij, Cambridge University
Press, 拢50/$69.95, ISBN 0521591147
IT鈥橲 official: marijuana does change your brain. Luckily for the many
millions of people worldwide who use the drug, the rot is so limited that only a
very subtle neurological test can detect it. But the longer you smoke marijuana,
the worse it gets.
We know this from a neat series of experiments by Nadia Solowij, a young
Australian researcher, whose work is reported for the first time in her
monograph Cannabis and Cognitive Functioning. She also critically
reviews other studies, and is well aware of the difficulties of delivering hard
facts. How can you do controlled psychological studies when the effects are so
slight? Another problem is that people who choose to smoke marijuana (usually
illegally) may be psychologically different from those who don鈥檛.
Advertisement
Solowij has found a way of separating the dope smokers from the abstemious.
Using a method widely employed in brain research, her subjects listen to tones
through headphones and hit a button when they hear one of particular location
(left or right ear), pitch and length. Marijuana smokers pass easier tests of
how well they focus their attention with flying colours, but not this one. They
make more mistakes, even though they are not under the drug鈥檚 influence at the
time. Analysis of their brain waves during the test shows that dope smokers are
not as good at filtering out distracting information.
We don鈥檛 know how important this impairment might be in real life. But we do
have a few hard facts which, as Solowij concludes, might help people to 鈥渕ake an
informed decision about whether to use the drug and, if they use, how much, how
long and how often鈥�. Everyone with a serious interest in the marijuana debate
should have a copy of this book, for its thorough review of the topic and for
its new data.