|
Can it give you cancer?
Data on cancer also generate mixed conclusions. A 1999 study of 173 patients with head and neck cancers found that pot smoking elevated the risk of such cancers. (Smokers of anything should also worry about lung cancer.) But it's not clear that THC is carcinogenic. The latest research suggests that THC may have a dual effect, promoting tumors by increasing free radicals and simultaneously protecting against tumors by playing a beneficial role in a process known as programmed cell death.
Is it addictive?
Those who believe you can't become physically or psychologically dependent on marijuana are wrong. At least three recent studies have demonstrated that heavy pot smokers who quit can experience such withdrawal symptoms as anxiety, difficulty sleeping and stomach pain. On the other hand, the risk of becoming dependent on marijuana is comparatively low. Just 9% of those who have used the drug develop dependence. By comparison, 15% of drinkers become dependent on alcohol, 23% of heroin users get hooked, and a third of tobacco smokers become slaves to cigarettes.
Does it make you stupid?
Potheads are dumber than nonusers, but only a little. Earlier this year, the Journal of the American Medical Association published a study of 102 near-daily marijuana users who wanted to quit. The authors found that the longer subjects had toked up, the worse their memories and attention spans. But they were hardly like Gobi, the Saturday Night Live wastoid who is so ruined he can barely talk. Participants who had used cannabis regularly for an average of 10 years fared significantly worse on only two of 40 indices of cognitive functioning (they had particular trouble estimating how much time had passed during a test). Those stout folks who had been smoking pot for an average of 24 years did significantly worse on 14 of the tests. But scientists can't say that marijuana causes such problems. "These long-term users may have been worse off in the first place, before they ever smoked marijuana," says Dr. Harrison Pope, a Harvard psychiatrist who wrote an editorial accompanying the study arguing that "we must live with uncertainty" on whether pot causes long-term cognitive impairments.
What about sex?
The latest studies suggest I needn't have fretted so much about pot's gonadal consequences. "Marijuana might interfere with [kids'] ability to go through puberty," says Dr. Adrian Dobs, co-author of a paper on the endocrine effects of the drug in the upcoming Journal of Clinical Pharmacology. "But the abnormalities seen are not really clinically significant." Despite tales of male potheads growing breasts, the long-term effects on adult glands are uncertain.
Do the sick really benefit?
So if marijuana can be harmful to healthy people—but usually isn't—could it actually be good for the sick? This is where the science gets scraggier—and in the absence of data, politics takes over. What we know is that healers have accumulated copious anecdotes on weed's powers over the past 4,700 years. Understanding Marijuana author Earleywine credits a (possibly mythical) Chinese emperor with introducing the plant as a treatment for gout around 2700 B.C. But the emperor also thought his pot potion would help memory, making him the first of many fans to aggrandize the drug's medical potential. The ancient Greek doc Galen even used the drug to treat flatulence.
The A.M.A. issued a report last year summarizing the body of knowledge about medical marijuana. It's shockingly slim. Dr. Abrams in San Francisco has produced some of the clearest evidence to date of pot's therapeutic value. Even though his clinical trial was designed merely to investigate whether marijuana is safe for HIV patients, he also turned up data that anyone who ever had the munchies already knew: pot makes you hungry. Test subjects who smoked marijuana gained an average of 6.6 lbs. during the trial, compared with 2.4 lbs. for the group taking the placebo. Some other findings from the A.M.A. report:
NAUSEA Patients who are HIV-positive or undergoing chemotherapy can have trouble keeping food down, so anything that helps them eat is significant—though not necessarily for the reasons marijuana boosters think. Pot's ability to enhance appetite may have more to do with its high and less to do with any direct effects on nausea. Only 20% to 25% of patients in two 1980s trials could completely control vomiting with marijuana; other drugs work better for emesis. Still, the A.M.A. recommended more studies on marijuana for those who don't respond to the other drugs, and it notes that for those feeling sick, inhaling a substance may be more palatable than swallowing a pill.
GLAUCOMA Marijuana does reduce pressure on the eyeball, about 25%, but the drug isn't always practical as a glaucoma treatment. Many who have the disease are elderly and can't tolerate pot's tendency to raise heart rates.
SPASTICITY Marijuana can help people with spasticity (extreme muscle tension) and tremor due to multiple sclerosis and trauma. But the drug hasn't been rigorously compared with the standard antispastic treatments.
PAIN In patients with postoperative pain, THC is more effective than a placebo, and some reports suggest smoking pot may reduce the need for highly addictive opioids. But the A.M.A. says better-designed studies are needed to properly evaluate pot as a painkiller. Several are under way. In California, five teams of researchers are conducting studies of marijuana as an analgesic, particularly for cancer and nerve pain.
 |
 |
 |
NATION
 Sniper-Suspect's Military Record
John Allen Muhammad was not a standout soldier, but he was a 90 percent marksman
TECHNOLOGY
Broadband Service
Whether you're new to the Web or a wily veteran, we offer some tips on finding the best high-speed access for you
|
 |
WORLD
A Nation in the Dark
Shortages of food and electricity leave North Korea desperate for aid and investment
ARTS
High Art of Jackass
Megastar masochist Johnny Knoxville creates a new kind of comedy, a movie all about hurting himself
|
|
|
 |
|
