Marijuana Science

In 1970, in response to marijuana’s rapidly rising popularity, Congress authorized $1 million for a national commission to study marijuana.  The National Commission on  Marihuana and Drug Abuse , generally referred to as the Shafer Commission, was headed by former Governor Raymond Shafer of Pennsylvania.  Among it twelve other members were four physicians, two lawyers, and four members of Congress.

The Shafer Commission reviewed claims about marijuana’s dangers dating back to the 1920s, some of which were still widely believed in the 1970s.  The commission hired consultants to review the scientific evidence.  Where important evidence was missing, the commission funded original studies.  It also held hearings around the country at which lawyers, physicians, researchers, educators, student, and law enforcement officials presented their opinions about marijuana, its effects, and the laws rohibiting its sale and use.

The Shafer Commission found no convincing evidence that  marijuana caused crime, insanity, sexual promiscuity, and a motivational syndrome, or that marijuana was a stepping stone to other drugs.   Animal studies suggested that no dose of marijuana would be fatal to humans, and that even very large doses of marijuana did not damage tissue or organs.  One of the commission’s own studies, in which researchers gave men in a laboratory unlimited access to marijuana for twenty-one days, revealed no psychological or intellectual impairment following high-dose use.  Research funded by the U.S. government in Jamaica and Greece found no physical or mental problems among men who had used marijuana heavily for many years.  Numerous studies showed that marijuana did not produce physical dependence and withdrawal, even after long-term, high-dose use.

The Shafer Commission understood that not drug used by humans was ever completely safe.  Given the known harmful effects of smoking tobacco, commission members assumed that smoking marijuana could damage the lungs of users.  They worried that driving under the influence of marijuana might cause accidents.  Like most other Americans, members of the commission thought kids should not use marijuana. Commission members also worried that long-term heavy marijuana use by adults could lead to social maladjustment.

However, they felt that  “marihuana related problems, which occur only in heavy, long-term users,”  had “been over-generalized and over’ dramatized.” Based on a substantial body of scientific research, the Shafer Commission concluded that “from what is now known about the effects of marihuana, its use … does not constitute a major threat to public health.” The Shafer Commission hoped that its review of the scientific evidence would help resolve the social conflict over marijuana policy, a conflict that had been brewing in American society for more than a decade.  By 1972, when the commission’s report was issued, more than twenty-four million Americans had used marijuana.  Among youth, marijuana had become a badge of rebellion.

They were skeptical of earlier claims that marijuana caused crime and insanity.  They also distrusted newer claims that marijuana cause psychological and biological damage.  Large numbers of young people openly defied the law by smoking marijuana in public.  Arrests for marijuana offenses had been increasing steadily.  Youthful marijuana users with no previous criminal records were being sent to prison for possessing small amounts of marijuana.  For all of these reasons and others, the Shafer Commission concluded that marijuana  *policy*  had become more damaging to American society than marijuana.

“Recognizing the extensive degree of misinformation about marihuana,” the commission “tried to  *demythologize * it” so that a more rational discussion of marijuana policy could occur.

The Shafer Commission’s recommendation for marijuana policy, endorsed by all thirteen members, was to retain the prohibition against marijuana’s cultivation and sale but to eliminate state and federal criminal penalties for marijuana possession and use.  This recommendation was endorsed by mainstream organizations such as the American Bar Association, the American Medical Association, the American Public Health Association, the National Council of Churches, the National Education Association, and the New York Academy of Medicine.  In separate reviews of the scientific evidence, several independent scholars agreed with the Shafer Commission that moderate marijuana use was not very dangerous.

Around the same time, government-appointed commissions in Britain, Canada, Australia, and the Netherlands also concluded that the risk of marijuana use was too small to justify harsh criminal sanctions.

Columbia University anesthesiologist Gabriel Nahas, a longtime opponent of marijuana use in the United States and his native Egypt, publicly challenged the Shafer Commission.  In 1974, Nahas helped Senator James Eastland organize Judiciary Committee hearings explicitly for the purpose of refuting the commission’s findings.  Only witnesses in favor of marijuana prohibition were invited.  All complained that the Shafer Commission had ignored evidence of marijuana;s social and moral dangers.  Witnesses described marijuana’s detrimental impact on motivation, personality, judgment, intellectual capacity, and the personal hygiene of users.  They reported that marijuana molecules got trapped in the brain.  As a result, they said, people who use marijuana only once a week were constantly intoxicated.

Speakers testified about marijuana addiction and marijuana-induced violence.  They claimed that marijuana diminished people’s ability to resist homosexual advances, and made them more susceptible to communist propaganda. They said that marijuana use had already led many college students into heroin addiction.

Witnesses at the Eastland hearings also claimed that the Shafer Commission had ignored scientific evidence of marijuana’s biological dangers.  Many witnessed had themselves conducted studies looking for marijuana-related biological toxicity.  One witness claimed to have found evidence of brain damage in young people who smoked marijuana.  Another said he had found serious lung damage in U.S. soldiers who had smoked hashish for less than a year.

Another said his study showed lowered testosterone levels and sperm counts in men who smoked marijuana.  Some Eastland witnesses had given large doses of THC to animals.  They claimed to have ground hormone deficiencies, infertility, and fetal damage.  One scientist reported that after forcing rhesus monkeys to inhale marijuana smoke, he found evidence of irreversible brain damage.  Other researchers reported the results of cellular studies, in which they had exposed human cells to THC in laboratory petri dishes. They said THC produced chromosomal abnormalities and evidence of immune deficiency.

Every witness at the Eastland hearings warned that decriminalizing marijuana would be a social disaster.  They predicted that marijuana use would skyrocket and that marijuana problems would reach epidemic proportions. Several witnesses warned that because more potent forms of marijuana had become available, all marijuana’s harmful effects would grow in prevalence and severity.  Senator Eastland predicted that if marijuana use by youth continued, American society faced certain destruction:

Our country has been caught up in a marihuana-hashish epidemic…. If the epidemic is not rolled back, our society may be largely taken over by a[/su_color_text]“marhuana culture”[/su_color_text] –a cuklture motivated … by a consuming lust for self-gratification, and lacking any higher moral guidance.  Such a society could not long endure.

During the past twenty-five years, the National Institute on Drug Abuse (NIDA) has funded research into nearly every claim made at the Eastland hearings.  Researchers have compared sex hormone levels and brain-wave patterns in marijuana users and nonusers. [/su_color_text] They have looked for abnormalities in the sperm of men who use marijuana, and have looked for damage to the children of women who smoked marijuana during pregnancy.[/su_color_text] Medical scientists have examined lung cells taken from long-term marijuana smokers, and have given them repeated tests of pulmonary function.

Social scientists have administered personality, social adjustment, and intelligence tests to marijuana users and nonusers.  They have compared the grades of students who use marijuana with the grades of students who do not, and the wages of workers who use marijuana with the wages of workers who do not.

Researchers have examined data on driving facilities for evidence of a relationship between marijuana use and highway accidents.  Epidemiologists have looked for a link between using marijuana and the use of their illegal drugs.  In laboratory studies, researchers have given marijuana to people to evaluate marijuana’s effects on memory, motivation, psycho-motor skills, and social interaction.  Other researchers have given large doses of THC to people, rats, mice, and monkeys every day for months, to see if physical dependence to marijuana develops.  Scientists have exposed human cells to THC or marijuana smoke in the laboratory, then looked for cellular abnormalities under a microscope.

In 1982, committees of the Institute of Medicine (IOM) and the World Health Organization (WHO) reviewed the research on marijuana, including ten years of investigation subsequent to the Shafer Commission’s review in 1972. Neither committee found convincing evidence of biological harm, psychological impairment, or social dysfunction among people who used marijuana moderately.  Studies indicated that some long-term heavy marijuana smokers had problems, but no study indicated that marijuana had directly caused them.  Instead, researchers consistently found that high-dose users with serious psychological and social adjustment problems usually had these problems before they began using marijuana.

Although studies of humans generally failed to find evidence of biological harm from marijuana, the IOM and WHO committees were troubled by the large number of animal and cellular studies suggesting *possible *biological toxicity.  Although most of the research reported at the Eastland hearings had not been confirmed by other investigators, new claims had appeared, based on additional animal and cellular studies.  Committee members were not convinced that animal and cellular studies were relevant to humans.  Yet they were unwilling to dismiss them entirely.  Neither report contained strong warnings about marijuana’s dangers.  However, the 1982 IOM and WHO reports were more cautious than the Shafer’s Commission’s report a decade earlier.

After 1982, government support for research into marijuana’s effects increased steadily.  In 1982, NIDA’s marijuana research budget was about $3 million.  By 1987 it was $15 million and by 1990 it was $26 million.  Much of this research has focused on the claims of biological toxicity first made in the early 1970s.  In cellular studies, scientists show tha large doses of THC or marijuana smoke regularly disrupt the function of cells in laboratory cultures.  in animal studies, researchers are able to produce a variety of biological effects, particularly if they inject THC directly into the
animals’ veins, abdominal cavities, or brains.  In animal and cellular studies, scientists have repeatedly found biological harms that have never been found in human marijuana users–for example, infertility, brain damage, immune impairment, and physical addiction.

Unlike in the 1970a, NIDA now funds few studies of human marijuana users with nonusers, rarely found evidence of physiological or psychological harm, intellectual impairment, or social dysfunction related to marijuana.  When differences were found, they were rarely confirmed by additional studies. Today, when researchers study people, they almost always compare long-term heavy marijuana users with occasional users or nonusers.  Heavy marijuana users tend to differ from occasional users and nonusers in many ways other than their use of marijuana.  For example, most heavy marijuana users are male, most have used many psychoactive drugs, and many have multiple problems that preceded their use of marijuana.  As a result, these studies may identify adverse characteristics in marijuana users that are actually due to factors other than marijuana use.

By administering multiple tests, researchers increase the likelihood that some positive findings will occur by statistical chance.  By using new technologies, researchers find subtle differences between marijuana users and nonusers that could not be detected previously.  For example, using computer-generated quantitative analysis, researchers recently found“statistically significant” differences between the brain-wave patterns of heavy marijuana users and nonusers–differences that have not been associated with any real life psychological or intellectual impairment.

In 1972, the Shafer Commission warned, “Science has become a weapon in a propaganda battle.”  This statement is more true today than then.  NIDA funds research to find harm from marijuana.  NIDA and other government agencies then disseminate negative findings to Congress, the media, and the public through official reports, press releases, and drug education pamphlets.  Findings from animal and cellular studies are used and cited as evidence of marijuana’s biological harms, even when researchers have consistently found no such harm in humans.  Very modest findings are presented as “significant”.  Statistical associations–for example, between heavy marijuana use and juvenile delinquency or heavy marijuana use and the use of cocaine–are used to imply a causal relationship.  Studies showing no effect–or a positive effect related to marijuana–are ignored completely.

In short, science is used selectively to support the claim that marijuana s dangers have been verified scientifically. Our review of the scientific literature leads us to conclude that marijuana is no more dangerous to humans that the Shafer Commission believed in 1972. Indeed, the research shows that in some respects, marijuana is less dangerous than the Shafer Commission suspected.  In 1995, a committee of the Dutch government said, “everything we now know … leads to the conclusion that the risks of cannabis use cannot in themselves be described as ‘unacceptable.’ “The same year, the editors of [/su_highlight]*Lancet*[/su_highlight], a British medical journal, stated without equivocation that “the smoking of cannabis, even long term, is not harmful to health.”  In the following chapters, we review the thirty years of scientific evidence on which the Dutch government and the  *Lancet * based these conclusions.


MARIJUANA HAS NO MEDICAL VALUE.  Safer, more effective drugs are available. They include a synthetic version of THC, marijuana’s primary active ingredient, which is marketed in the United States under the name Marino.

There is no evidence to prove marijuana’s use in chemotherapy.  There are numerous alternative drugs that obviate the need to even pursue research on the subject.

Smoking pot does not qualify as a medicine. . . . The marijuana as medicine issue is a carefully orchestrated campaign . . . by aging hippies, lawyers, and marijuana users who are imposing a cruel hoax on sick and dying people.

Considering the known effects of marijuana on short-term memory, it seems probable that marijuana would impair . . . the patient’s ability to remember to take other lifesaving . . . medicines.

The pro-drug lobby exploits the suffering of patients with chronic illness . . . as part of a strategy to legalize marijuana for general use.
There could be no worse message to young people. .Just when the nation is trying its hardest to educate teenagers not to use psychoactive drugs, now they are being told that marijuana [is a ] medicine.


stimulating appetite in AIDS patients, and reducing intraocular prsessure in people with glaucoma.  There is also appreciable evidence that marijua reduces muscle spasticity in patients with neurological disorders.  A synthetic THC capsule is available by prescription, but it is not as effective as smoke marijuana for many patients.

Pure THC may also produce more unpleasant psychoactive side effects than smoked marijuana.  Many people use marijuana as a medicine today, despite its illegality.  In doing so, they risk arrest and imprisonment.