a review of the scientific evidence, by Lynn Zimmer, Ph.D. and John P. Morgan, M.D.

Marijuana Myths Marijuana Facts
a review of the scientific evidence
by Lynn Zimmer, Ph.D. and John P. Morgan, M.D.
The Lindesmith Center, 1997
241 pages softcover, $12.95

Marijuana is highly addictive. Marijuana is a gateway drug. Marijuana is more potent today than in the past.

These are a few of the twenty common assumptions about marijuana that Lynn Zimmer, an Associate Professor of Sociology at Queens College, City University of New York, and John Morgan, physician and Professor of Pharmacology at City University of New York Medical School, examine in their current release Marijuana Myths Marijuana Facts. Zimmer and Morgan devote a chapter to each of these 'marijuana myths' in which they examine the existing scientific evidence to see whether these assertions hold true. Their conclusion, on almost all counts, is a resounding no.

The book, the first release from the drug research foundation, The Lindesmith Center, is exhaustively researched, with about one-fifth of the volume taken up by references. However, the text is written in a very simple, nontechnical style. It is not, by design, a scientific treatise, but rather a summary and analysis of existing research. Therefore, it is valuable both as an overview for parents, educators, or anyone wanting an introduction to the subject, and as a great reference tool for serious drug policy researchers.

The authors definitely have an agenda, and they acknowledge this up front by saying that they set out to "promote discussion of less punitive [drug] policies... by presenting the facts about marijuana." They achieve this most effectively when they take much cited claims used in antidrug campaigns and show us exactly where the statistics come from. For example, in the chapter on Marijuana, Sex Hormones and Reproduction, Zimmer & Morgan quote the publication "Marijuana: Tips for Teens" published in 1995 by the Center for Substance Abuse Prevention. This pamphlet includes the oft-repeated claim that "marijuana .... [causes] lower sperm counts and difficulty having children in men." This is a belief that is widely accepted, even by some marijuana users and activists. So where does the evidence come from? Well, it turns out that these claims stem from a 1974 study conducted by a researcher named Robert Kolodny in which he reported that frequent marijuana users had lower sperm counts than occasional users. However, subsequent research has failed to repeat these findings. In fact, in a 1979 study, men spent thirty days in a closed lab smoking up to twenty marijuana cigarettes a day. When researchers examined their sperm counts, none were outside normal ranges.

Most of the chapters do not discuss actual studies in such a detailed manner, which occasionally weakens the author's arguments since the reader must take their interpretation of the evidence on faith. However, I found most of their arguments compelling and their reasoning solid. Marijuana Myths is an interesting overview of a controversial topic, and a solid reference tool for further research.