244 Marijuana
search finds no evidence that marijuana causes human birth defects. A study
examining infants of adolescent mothers who used marijuana during preg-
nancy noted some “minor” birth defects, but even these researchers did not
conclude that marijuana was necessarily the cause. Studies of newborns’ birth-
weights have been inconclusive about an impact from prenatal marijuana ex-
posure. No major effect on muscular coordination and balance turned up in
an examination of preschool children having prenatal marijuana exposure, but
investigators cautioned that the tests lacked measures of subtle skills. Behavior
problems have been reported among children who had prenatal marijuana
exposure, but we do not know whether those problems were caused by mar-
ijuana or by years of exposure to a particular type of parent. Investigators
watching development of children up to age 5 found no difference attributable
to maternal marijuana use during pregnancy; differences existed but were
ascribed to home environment and schooling. Examination of reading and
language abilities in children aged 9 to 12 years found no significant impact
from prenatal marijuana exposure. Some researchers believe they have found
problems caused by prenatal marijuana, but most research is consistent with
marijuana being benign.
Marijuana’s THC passes into human milk, and researchers report deficient
development of muscle and limb coordination among infants nursed on such
milk. One case report noted the THC level in milk was eight times higher
than the mother’s blood level.
Additional information.Marijuana and hemp come from different portions
of the same plant,Cannabis sativa. Leaves, flowers, and resin are the illegal
drug marijuana; the resin is also called hashish. Stalks and seed (if processed
so it will not germinate) are the legal commercial product hemp. The terms
hempandmarijuanaare sometimes used interchangeably, but such use is in-
correct. After marijuana was outlawed in the 1930s, hemp raising continued
to thrive because law enforcement authorities of the era were familiar with
the industry and understood that crops were not entering the illegal drug
market even though the plants had leaves and flowers and resin. During
World War II the federal government subsidized hemp farming to replace
natural fiber supplies cut off by the war. In the 1950s subsidies finally stopped,
and the American hemp industry also stopped because it could no longer
make money at the unsubsidized world market price.
Some food products contain hemp components and can cause false positives
for marijuana in urine drug screen tests. Hemp lotions and creams rubbed on
the skin produce marijuana chemicals in urine, but not enough to cause false
positives in a drug screen.
“Locoweed” and “stinkweed” are nicknames for both jimson weed and mar-
ijuana, but the substances are different.
Additional scientific information may be found in:Carlson, B.R., and W.H. Edwards. “Human Values and Marijuana Use.”International
Journal of the Addictions25 (1990): 1393–401.
Fried, P., et al. “Current and Former Marijuana Use: Preliminary Findings of a Lon-
gitudinal Study of Effects on IQ in Young Adults.”CMAJ: Canadian Medical
Association Journal166 (2002): 887–91.