It turns out that the study of marijuana's health effects is at once more complex and less advanced than you might imagine. "Interpretations [of marijuana research] may tell more about [one's] own biases than the data," writes Mitch Earleywine in Understanding Marijuana: A New Look at the Scientific Evidence, published in August by Oxford. For example: "Prohibitionists might mention that THC [delta-9 tetra-hydrocannabinol, the smile-producing chemical in pot] often appears in the blood of people in auto accidents. Yet they might omit the fact that most of these people also drank alcohol. Antiprohibitionists might cite a large study that showed no sign of memory problems in chronic marijuana smokers. Yet they might not mention that the tests were so easy that even a demented person could perform them."
The science
The science of marijuana--especially its potential medical uses--is malleable because it's so young and so contradictory. Although preliminary data are promising, scientists haven't definitively shown that the drug can safely treat nausea or pain or anything, really. Some experts claim the U.S. government has sabotaged medical-marijuana research, and there is evidence to support them. Even so, in the past few years scientists have made rapid advances in their basic understanding of how Cannabis sativa works. By 1993, researchers had found the body's two known receptors for cannabinoids, the psychoactive chemicals in the plant (THC is the main one, but there are at least 65 others). Since then, there has been important new work in several fields that users, potential users and former users should know about--and that voters should take into account before deciding on Proposition 19
Can it kill you?
No one has ever died of THC poisoning, mostly because a 160-lb. person would have to smoke roughly 9000 joints in ten minuets to reach a lethal dose.
