Marijuana is the most commonly used illicit drug in the United States. A dry, shredded green/brown mix of flowers, stems,
seeds, and leaves of the hemp plant Cannabis sativa, it usually is smoked as a cigarette (joint, nail), or in a pipe (bong).
It also is smoked in blunts, which are cigars that have been emptied of tobacco and refilled with marijuana, often in combination
with another drug. Use also might include mixing marijuana in food or brewing it as a tea. As a more concentrated, resinous
form it is called hashish and, as a sticky black liquid, hash oil. Marijuana smoke has a pungent and distinctive, usually
sweet-and-sour odor. There are countless street terms for marijuana including pot, herb, weed, grass, widow, ganja, and hash,
as well as terms derived from trademarked varieties of cannabis, such as, Northern Lights®, Fruity Juice®, Afghani #1®, and
a number of Skunk varieties.
The main active chemical in marijuana is THC (delta-9-tetrahydrocannabinol). The membranes
of certain nerve cells in the brain contain protein receptors that bind to THC. Once securely in place, THC kicks off a series
of cellular reactions that ultimately lead to the high that users experience when they smoke marijuana.
Depression, anxiety, and personality disturbances have been associated with marijuana use. Research clearly demonstrates
that marijuana has potential to cause problems in daily life or make a person’s existing problems worse. Because marijuana
compromises the ability to learn and remember information, the more a person uses marijuana the more he or she is likely to
fall behind in accumulating intellectual, job, or social skills. Moreover, research has shown that marijuana’s adverse
impact on memory and learning can last for days or weeks after the acute effects of the drug wear off.
smoke marijuana get lower grades and are less likely to graduate from high school, compared with their non-smoking peers.
A study of 129 college students found that, for heavy users of marijuana (those who smoked the drug at least 27 of the preceding
30 days), critical skills related to attention, memory, and learning were significantly impaired even after they had not used
the drug for at least 24 hours. The heavy marijuana users in the study had more trouble sustaining and shifting their attention
and in registering, organizing, and using information than did the study participants who had used marijuana no more than
3 of the previous 30 days. As a result, someone who smokes marijuana every day may be functioning at a reduced intellectual
level all of the time.