Marijuana's damaging effects
Scientists say pot's health-related risks are real but small in some instances.
Marijuana is the most widely used illicit drug in the country -- an estimated 25 million Americans smoked it within the last year and close to 100 million have smoked it at least once in their life, according to the most recent National Survey on Drug Use and Health by the federal Substance Abuse and Mental Health Services Administration.
Rates and severity of marijuana addiction pale in comparison to that of legal addictive drugs, alcohol and nicotine, according to the Advisory Council on the Misuse of Drugs, a panel of independent experts advising the British government, in a rare head-to-head, scientific comparison.
Yet, the fact is, recreational use can lead to addiction, and inhaling marijuana smoke is unhealthful for the lungs. Some researchers argue that marijuana may predispose heavy users to mental illnesses such as psychosis and depression.
How big are these risks and how should they be measured against health benefits? "The FDA has ruled that marijuana has no medical benefits, but its harms are well known and proven," says Tom Riley, a spokesman for the White House Office of National Drug Control Policy, referring to an April 2006 statement released by the FDA and several other federal agencies concluding that smoking marijuana was not of medicinal use.
For comparison's sake, Riley cites the prescription drug Vioxx. The FDA, he notes, pulled Vioxx off the market in spite of its proven efficacy, because it created problems in a small number of people.
Then, too, the number of people adversely affected by marijuana use is large, Riley says. "There are more teens in drug treatment for marijuana dependence than for alcohol or any other drug," he says.
Marijuana is a Schedule 1 drug by the Drug Enforcement Administration's Controlled Substances Act, a classification reserved for drugs carrying the highest risk for addiction and no medical benefit.
Scientists have reviewed the weed's risks and find them to be real, but small. Ten years ago, the Institute of Medicine reviewed the scientific evidence about marijuana at the request of the Office of National Drug Control Policy. The 1999 report states that, "except for the harms associated with smoking, the adverse effects of marijuana use are within the range of effects tolerated for other medications."
In February, the American College of Physicians, the nation's second-largest physicians group, released a position paper in support of medical-marijuana research, protecting doctors from criminal prosecution and rescheduling marijuana as a less harmful drug.
