Marijuana 243age have been seen in marijuana smokers but not in tobacco smokers. Mari-
juana smokers typically use big puffs and deep inhalations, held for a long
period of time. Such a technique deposits larger quantities of damaging ma-
terials in lungs than the ordinary tobacco-smoking technique. Efforts to doc-
ument lesser-known health risks have been flawed or outright unsuccessful.
Reports of physical disease in marijuana users often fail to account for other
possible (and perhaps more likely) causes.
Despite conceivable health hazards from marijuana, it seems safe in mod-
eration, no more dangerous than many foods (such as items high in sugar,
salt, fat, and cholesterol). The natural product is extraordinarily safe from a
dosage standpoint.^1 No human fatality has been confirmed, although cattle
deaths have been reported after consuming bales of dried marijuana.
Abuse factors.Tolerance and dependence have been reported. A marijuana
abstinence syndrome is described as including physical and mental tenseness,
peevishness, less happiness, and diminished appetite. Such symptoms, how-
ever, sound much like the reasons many persons use marijuana. If a chronic
headache sufferer reported discomfort when pain relievers were unavailable,
that would not be considered evidence of dependence on and withdrawal
from pain relievers. Self-administration of a drug by laboratory animals is a
traditional sign of addictive potential, but researchers have mixed success in
getting animals to self-administer THC.
Drug interactions.Not enough scientific information to report, although it
is reasonable to assume interactions could be similar to those occurring with
dronabinol.
Cancer.Laboratory tests indicate that marijuana smoke can cause cancer.
Oral and lung cancer is reported among marijuana users, although we must
remember that typical users also smoke tobacco. One study did find that mar-
ijuana, even when tobacco use is accounted for, increases chances of getting
head and neck cancer. One of the more impressive studies of marijuana’s
cancer-causing potential involved medical records of 64,888 persons and dis-
covered that people who used marijuana, whether frequently or infrequently,
were in general no more likely to get cancer than anyone else. That study did
find evidence, however, that marijuana promotes prostate and cervical cancer.
Researchers have found that children are more likely to develop acute non-
lymphocytic leukemia if their mothers used marijuana during pregnancy. This
is a rare disease; in a population of 1 million children, about 5 will have the
affliction. The disease is also associated with pesticide exposure, and investi-
gators are uncertain whether pesticide contamination of marijuana is a more
important factor than marijuana itself.
Chromosome damage can indicate a potential for development of cancer.
Some laboratory and animal experiments indicate marijuana causes chromo-
some damage, but a study found human chromosome abnormalities to be
about the same in moderate users of marijuana and nonusers. Researchers
conducting one human study sent the same samples to two laboratories, but
neither lab was able to find chromosome damage attributable to marijuana.
Pregnancy.Normally we think of marijuana as a recreational substance, but
some women use it to ease discomforts of pregnancy and childbirth. Mari-
juana chemicals pass from a pregnant woman into the fetus. Almost all re-