The Health Effects of Marijuana

In this installment of a regular feature, the author attempts to present a balanced assessment of the health effects of marijuana.

| May/June 1981

069 health effects of marijuana - Fotolia - Richard Villalon

Although research into the health effects of marijuana often produced contradictory results, relatively disinterested assessments concluded the smoke irritates the throat and lungs and has as many carcinogenic compounds as tobacco.


Dr. Tom Ferguson wrote the Medical Self Care column in this magazine in the early 1980s. This issue's column was guest authored by Michael Castleman, managing editor of Medical Self-Care magazine.   

Two years ago, investigators at the UCLA Pulmonary Research Laboratory published the abstract of a study on the respiratory effects of heavy marijuana smoking among 75 young men who consumed an average of five marijuana cigarettes, or joints, a day for two months. Among other less dramatic findings, this "Tashkin Report" suggested: "Smoking four joints a week may cause more respiratory impairment than smoking 16 cigarettes a day."  

The wire service that picked up the story dropped the word "may," and the nation learned that the lung damage caused by four joints equaled that caused by 112 cigarettes.

Later that year, Peter Bensinger (a director of the federal Drug Enforcement Agency) told a graduating class at the FBI Academy that smoking five joints a week introduced more carcinogens into the lungs than smoking a pack of unfiltered cigarettes a day. His remarks were also picked up by the wire services.

Extrapolations like these occur with disturbing frequency. Because marijuana is controversial—and illegal—the atmosphere surrounding the health effects of marijuana is highly charged, and the available data conflict at almost every turn. In fact, if all marijuana researchers are correct in their methodological criticisms of each other's work, none of the reported results can be trusted.

On the other hand, no reputable authorities argue that "grass" is completely safe, not even the legalization lobby, the National Organization for the Reform of Marijuana Laws (NORML). Clearly, lung cells are extremely delicate, and any long-term exposure to hot particulate combustion products—which contain a large number of carcinogens—can be assumed to cause some damage.

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