CLAIM #8:
MARIJUANA CAUSES BRAIN DAMAGE
Critics state that marijuana damages brain cells and that this damage, in turn, causes memory loss, cognitive impairment, and difficulties in learning.
THE FACTS The original basis of this claim was a report that, upon post-mortem examination, structural changes in several brain regions were found in two rhesus monkeys exposed to THC. Because these changes primarily involved the hippocampus, a cortical brain region known to play an important role in learning and memory, this finding suggested possible negative consequences for human marijuana users.
Additional studies, employing rodents, reported similar brain changes.
However, to achieve these results, massive doses of THC-up to 200 times the psychoactive dose in humans-had to be given.
In fact, studies employing 100 times the human dose have failed to reveal any damage.
In the most recently published study, rhesus monkeys, through face-mask inhalation, were exposed to the equivalent of 4-5 joints per day for an entire year.
When sacraficed seven months later, there was no observed alteration of hippocampal architecture, cell size, cell number, or synaptic configuration.
The authors conclude that:

"while behavioral and neuroendocrinal effects were observed during marijuana smoke exposure in the monkey, residual neuropathological and neurochemical effects of marijuana exposure were not observed seven months after the year-long marijuana smoke regimen."

Thus, twenty years after the first report of brain-damage in two marijuana-exposed monkeys, the claim of physiological damage to brain cells has been effectively disproven.
No post-mortem examinations of the brains of human marijuana users have ever been conducted. However, numerous studies have explored marijuana's effect on brain-related cognitive functions. Many employ an experimental design-in which subjects are given marijuana in a laboratory setting, and then compared to controls on a variety of measures involving attention, learning, and memory.
In a number of studies, no significant differences were detected.
In fact, there is substantial research demonstrating that marijuana intoxication does not impair the retrieval of information learned previously.
However, there is evidence that marijuana, particularly in high doses, may interfere with users' ability to transfer new information into long-term memory.
While there is general agreement that, while under the influence of marijuana, learning is less efficient, there is no evidence that marijuana users-even long-term users-suffer permanent impairment.
Indeed, numerous studies comparing chronic marijuana users with non-user controls have found no significant differences in learning, memory recall, or other cognitive functions.
 
 
 

CLAIM #9:
MARIJUANA IS AN ADDICTIVE DRUG
It is now frequently stated that marijuana is profoundly addicting and that any increase in prevalence of use will lead inevitably to increases in addiction.
THE FACTS Essentially all drugs are used in "an addictive fashion" by some people.
However, for any drug to be identified as highly addictive, there should be evidence that substantial numbers of users repeatedly fail in their attempts to discontinue use and develop use-patterns that interfere with other life activities.
National epidemiological surveys show that the large majority of people who have had experience with marijuana do not become regular users.
In 1993, among Americans age 12 and over, about 34% had used marijuana sometime in their life, but only 9% had used it in the past year, 4.3% in the past month, and 2.8% in the past week.
A longitudinal study of young adults who had first been surveyed in high school also found a high "discontinuation rate" for marijuana.
While 77% had used the drug, 74% of those had not used in the past year and 84% had not used in the past month.
Of course, even people who continue using marijuana for several years or more are not necessarily "addicted" to it.
Many regular users-including many daily users-consume marijuana in a way that does not interfere with other life activities, and may in some cases enhance them.
There is only scant evidence that marijuana produces physical dependence and withdrawal in humans.
When human subjects were administered daily oral doses of 180-210 mg THC-the equivalent of 15-20 joints per day-abrupt cessation produced adverse symptoms, including disturbed sleep, restlessness, nausea, decreased appetite, and sweating.
The authors interpreted these symptoms as evidence of physical dependence.
However, they noted the syndrome's relatively mild nature and remained skeptical of its occurrence when marijuana is consumed in usual doses and situations.
Indeed, when humans are allowed to control consumption, even high doses are not followed by adverse withdrawal symptoms.
Signs of withdrawal have been created in laboratory animals following the administration of very high doses.
Recently, at a NIDA-sponsored conference, a researcher described unpublished observations involving rats pre-treated with THC and then dosed with a cannabinoid receptor-blocker.
Not surprisingly, this provoked sudden withdrawal, by stripping receptors of the drug.
This finding has no relevance to human users who, upon ceasing use, experience a very gradual removal of THC from receptors.
The most avid publicizers of marijuana's addictive nature are treatment providers who, in recent years, have increasingly admitted insured marijuana users to their programs.
The increasing use of drug-detection technologies in the workplace, schools and elsewhere has also produced a group of marijuana users who identify themselves as "addicts" in order to receive treatment instead of punishment.
 
 
 

CLAIM #10:
MARIJUANA-RELATED MEDICAL EMERGENCIES ARE INCREASING
As evidence of its harmful effects, prohibition advocates point to dramatic increases in emergency-room episodes related to marijuana ingestion.
THE FACTS Data gathered by the Drug Abuse Warning Network (DAWN) show a recent increase in "marijuana mentions" by people seeking treatment in hospital emergency rooms.
Using a one-page form, emergency-room personnel record "drug abuse episodes," note the presence or absence of alcohol as a contributing factor, and list up to four other drugs recently consumed by the patient.
Although DAWN began compiling data in the 1970s, recent changes in recording procedures, the hospital selection, and methods of statistical estimation prevent comparisons of data gathered prior to 1988 with those gathered recently.
Thus, discussion of emergency-room trends is limited to the years 1988 to 1993.
The lowest number of marijuana-mentions, recorded in 1990, was 15,706 (7.1 mentions per 100,000 population).
The highest was 29,166 (12.7 per 100,000 population), recorded in 1993.
Using these figures, an increase of 86% has been reported.
However, if 1988 is used as the "base year" instead-a year in which there were 19,962 marijuana mentions-the increase is reduced immediately by more than half, to 42%.
Despite marijuana being the most frequently used illicit drug, in emergency rooms, it remains the least often mentioned illicit drug.
In 1993, marijuana accounted for 6.25% of mentions, compared to 15.3% for cocaine and 9.8% for heroin. Even over-the-counter pain medications were mentioned more often than marijuana-comprising 9% of the total.
For youth aged 6 to 17, there were more mentions of marijuana than of heroin and cocaine-not because marijuana is more harmful to them but because these latter drugs are used so infrequently by young people.
In this age group, mentions of over-the-counter pain medications were substantially higher than those for marijuana.
While marijuana accounted for 6.48% of drug mentions by youth, over-the-counter pain medications accounted for 47%.
For the total population, not only is marijuana mentioned less frequently than other recreational drugs, it is seldom mentioned alone.
In 1992, in more than 80% of the drug-abuse episodes involving marijunana, at least one other drug was mentioned; and, in more than 40%, two or more additional drugs were mentioned.
Of 24,000 marijuana mentions in 1992, more than 13,000 involved alcohol and nearly 10,000 involved cocaine.
Despite recent increases in marijuana mentions, hospital emergency rooms are not flooded with marijuana users seeking medical attention.
In 1992, of 433,493 total drug mentions, only 4,464 -- about 1% -- involved the use of marijuana alone.
 
 
 

CLAIM #11:
MARIJUANA PRODUCES AN AMOTIVATIONAL SYNDROME
Marijuana is said to have a deliterious effect on society by making users passive, apathetic, unproductive, and unable (or unwilling) to fulfill their responsibilities.
THE FACTS The concept of an amotivational syndrome first appeared in the late 1960s, as marijuana use was increasing among American youth.
In the years since, despite the absence of an agreed-upon definition of the concept, numerous researchers have attempted to verify its occurrence.
Large-scale studies of high school students have generally found no difference in grade-point averages between marijuana users and non-users.
One study found lower grades among students reported to be daily users of marijuana, but the authors failed to identify a causal relationship and concluded that both phenomena were part of a complex of inter-related social and emotional problems.
In one longitudinal study of college students, after controlling for other factors, marijuana users were found to have higher grades than non-users and to be equally as likely to successfully complete their educations.
Another study found that marijuana users in college scored higher than non-users on standardized "achievement values" scales.
Field studies conducted in Jamaica, Costa Rica and Greece also found no evidence of an amotivational syndrome among marijuana-using populations.
In these samples of working-class males, the educational and employment records of marijuana users were, for the most part, similar to those of non-users.
In fact, in Jamaica, marijuana was often smoked during working hours as an aid to productivity.
The results of laboratory studies have been nearly as consistent.
In one study lasting 94 days, marijuana had no significant impact on learning, performance or motivation.
In another 31-day study, subjects given marijuana worked more hours than controls and turned in an equal number of tokens for cash at the study's completion.
However, in a Canadian study that required subjects in the marijuana group to consume unusually high doses, some reduction in work efficency was noted in the days following intoxication. Undoubtedly, when marijuana is used in a way that produces near-constant intoxication, other activities and responsibilities are likely to be neglected.
However, the weight of scientific evidence suggests that there is nothing in the pharmacological properties of cannabis to alter people's attitudes, values, or abilities regarding work.
 
 
 

CLAIM #12:
MARIJUANA IS A MAJOR CAUSE OF HIGHWAY ACCIDENTS
The detrimental impact of alcohol on highway safety has been well documented. Marijuana's opponents claim that it, too, causes significant impairment and that any increase in use will lead to increased highway accidents and fatalities.
THE FACTS In high doses, marijuana probably produces driving impairment in most people. However, there is no evidence that marijuana, in current consumption patterns, contributes substantially to the rate of vehicular accidents in America.
A number of studies have looked for evidence of drugs in the blood or urine of drivers involved in fatal crashes.
All have found alcohol present in 50 percent or more.
Marijuana has been found much less often. Furthermore, in the majority of cases where marijuana has been detected, alcohol has been detected as well.
For example, a recent study sponsored by the U.S. National Highway Traffic Safety Administration (NHTSA) involving analysis of nearly 2000 fatal accident cases, found 6.7 percent of drivers positive for marijuana.
In more than two-thirds of those, alcohol was present and may have been the primary contributor to the fatal outcome.
To accurately assess marijuana's contribution to fatal crashes, the positive rate among deceased drivers would have to be compared to the positive rate from a random sample of drivers not involved in fatal accidents.
Since the rate of past-month marijuana use for Americans above the legal driving age is about 12 percent, on any given day a substantial proportion of all drivers would test positive, particulary since marijuana's metabolites remain in blood and urine long after its psychoactive effects are finished.
A recent study found that one-third of those stopped for "bad driving" between the hours of 7 p.m. and 2 a.m.-mostly young males-tested positive for marijuana only.
To be meaningful, these test results would have to be compared to those from a matched control group of drivers.
A number of driving simulator studies have shown that marijuana does not produce the kind of psychomotor impairment evident with modest doses of alcohol.
In fact, in a recent NHTSA study, the only statistically significant outcome associated with marijuana was speed reduction.
A recent study of actual driving ability under the influence of cannabis-employing the same protocol used to test the impairment-potential of medicinal drugs-evaluated the impact of placebo and three active THC doses in three driving trials, including one in high-density urban traffic.
Dose-related impairment was observed in drivers' ability to maintain steady lateral position. However, even with the highest dose of THC, impairment was relatively minor-similar to that observed with blood-alcohol concentrations between .03 and .07 percent and many legal medications.
Drivers under the influence of marijuana also tended to drive more slowly and approach other cars more cautiously.
While recognizing some limitations of this study, the authors conclude that "THC is not a profoundly impairing drug.
 
 
 

CLAIM #13:
MARIJUANA IS A "GATEWAY" TO THE USE OF OTHER DRUGS
Advocates of marijuana prohibition claim that even if marijuana itself causes minimal harm, it is a dangerous substance because it leads to the use of "harder drugs" such as heroin, LSD, and cocaine.
THE FACTS Most users of heroin, LSD and cocaine have used marijuana.
However, most marijuana users never use another illegal drug.
Over time, there has been no consistent relationship between the use patterns of various drugs.
As marijuana use increased in the 1960s and 1970s, heroin use declined. And, when marijuana use declined in the 1980s, heroin use remained fairly stable.
For the past 20 years, as marijuana use-rates fluxuated, the use of LSD hardly changed at all. Cocaine use increased in the early 1980s as marijuana use was declining.
During the late 1980s, both marijuana and cocaine declined.
During the last few years, cocaine use has continued to decline as marijuana use has increased slightly.
In 1994, less than 16 percent of high school seniors who had ever tried marijuana had ever tried cocaine-the lowest percentage ever recorded.
In fact, as shown below, the proportion of marijuana users trying cocaine has declined steadily since 1986, when a high of more than 33 percent was recorded.
Percentage of Marijuana Users Ever Trying Cocaine, High School Seniors,
1975-1994 1975 1976 1977 1978 19791980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994
19 19 20 22 25 27 28 27 28 29 31 33 30 26 23 22 22 % 18 17 16 In short, there is no inevitable relationship between the use of marijuana and other drugs.
This fact is supported by data from other countries.
In Holland, for example, although marijuana prevalence among young people increased during the past decade, cocaine use decreased-and remains considerably lower than in the United States. Whereas approximately 16 percent of youthful marijuana users in the U.S. have tried cocaine, the comparable figure for Dutch youth is 1.8 percent.
Indeed, Holland's policy of allowing marijuana to be purchased openly in government-regulated "coffee shops" was designed specifically to separate young marijuana users from illegal markets where heroin and cocaine are sold.
 
 
 

CLAIM #14:
DUTCH MARIJUANA POLICY HAS BEEN A FAILURE
While American critics of marijuana prohibition often point to Holland as a model for an alternative policy, prohibition's supporters claim that Holland's permissiveness has had disasterous consequences, including escalating rates of drug use among youth.
THE FACTS In 1976, following the recommendations of two national commissions, the Dutch government revised many aspects of its drug policy.
While not legalizing marijuana, it adopted an "expediency principle," which directed police and prosecutors to ignore retail sale to adults as long as the circumstances of the sale do not constitute a public nuisance.
This change in policy was based on several factors, including:
* a principle of tolerance toward alternative lifestyles *
a finding that, compared to other illegal drugs, marijuana poses little risk to users
* a desire to protect marijuana users from the marginalization that accompanies arrest and prosecution *
a belief that separating the retail markets for "soft" and "hard" drugs decreases the likelihood that marijuana users will experiment with cocaine or heroin Following the policy change, marijuana sales emerged openly in coffee shops, which were required to follow a set of regulations, including a ban on advertising, sale of no more than 30 grams at a time, and a minimum purchase age of 18.
The sale of other drugs on the premises is strictly prohibited, and constitutes grounds for immediate closure by the police.
Local officials were also authorized to create additional regulations to protect the interests of the community-for example, limiting the number of coffee shops concentrated in any one area.
Since liberalization, marijuana use has increased in the Netherlands, although rates remain similar to those in neighboring European countries, and are generally lower than those in the United States. Marijuana Use Among Dutch Youth (ages 12-18) ever used past month 1984 4.8 % 2.3 % 1988 8.0 3.1 1992 13.6 6.5 Marijuana Use Among American Youth (ages 12-17) ever used past month 1985 23.2 % 11.2 % 1988 24.7 6.4 1993 11.7 4.9 Marijuana Use Among American Youth (high-school seniors) ever used past month 1985 54.2 25.7 1988 47.2 18.0 1993 35.3 15.6 While marijuana use-rates have increased in Holland, cocaine use-rates have not- indicating that separation of the "hard" and "soft" drug markets has prevented a "gateway effect" from developing.
In 1992, about 1.5% of 12 to 18 year-olds had ever tried cocaine and only .3% had used it in the past month.
Although there are some Dutch critics of Holland's liberalized marijuana policy, the government's official position remains steadfastly supportive of the 1976 initiative that decriminalized possession and retail sale. -- In one longitudinal study of college students, after controlling for other factors, marijuana users were found to have higher grades than non-users and to be equally as likely to successfully complete their educations.
Another study found that marijuana users in college scored higher than non-users on standardized "achievement values" scales.