An ongoing research project headed by associate professor of psychiatry Harrison Pope

had one subject who had smoked marijuana every day for a long time. To participate in the

research-which actually concerned not drug use but testosterone-he had to stop his marijuana

use. The man had been such a heavy use that, even four weeks after quitting, detectable

cannabis residue appeared in his urine. But one day soon thereafter he told Pope that he "woke

up and felt alert for the first time in years. The acute effects of marijuana, whose botanical name

is cannabis, are well documented, but scientists know far less about the residual, or long-term

results of its intake.

Marijuana is a drug made from the dried leaves and flowering tops of the hemp plant.

Marijuana has many psychological and physical effects. People usually smoke marijuana in

cigarettes or pipes, but it also can be mixed in with food and beverages. Almost all nations,

including the United States and Canada, have laws that prohibit the cultivation, distribution,

possession, and use of marijuana. Marijuana has many nicknames, including grass, pot, and

weed. It is also called cannabis, a word that comes from Cannabis sativa, the scientific name for


Marijuana contains more than 400 chemicals. When smoked, it produces over 2,000

chemical that enter the body through the lungs. These chemicals have a variety of immediate,

short-term effects. In addition, the repeated use of marijuana has been linked to a number of

long-term effects short- Term Effects of marijuana include both psychological and physical

reactions, known a s a high, consists of changes in the user's feelings and thoughts. Such

changes are caused mainly by THC, a chemical in marijuana that impairs brain function.

The effects of a marijuana high vary from person to person and from one time to

another in the same individual. In most cases, the high consists of a dreamy, relaxed state in

which users seem more aware of their senses and feel that time is moving slowly. Sometimes,

however, marijuana produces a feeling of panic and dread. The different reactions result partly

from the concentration of THC in the marijuana. Other factors, such as the setting in which

marijuana is used and the user's expectations, personality, and mood, also affects a person's

reaction. The short-term physical effects of marijuana include redness in the eyes and a rapid

heartbeat. The drug also interferes with a person's judgment, and coordination.

Long-Term Effects of marijuana are not completely known. But studies have shown that

some people who have used marijuana regularly for several months or longer develop serious

long-term problems. Use of marijuana harms memory and motivation. Some chronic users

suffer bronchitis, coughing, and chest pains. Marijuana smoke also contains cancer-causing

substances. Among males, marijuana use can reduce the production of sperm and of the male

sex hormone testosterone. Among females, it can cause menstrual irregularity and reduced

fertility. Extended use of marijuana also has a long-term psychological effect on many people.

These individuals lose interest i school, their job, and social activities.

Why people use marijuana

Most people who use marijuana begin to do so between the ages of 12 and 18. They try the

drug because of curiosity. Some people believe marijuana improves their talents and capabilities. But

scientists have found that marijuana impairs all abilities. Marijuana may increase a person's

willingness to accept new ideas without determining whether they are true or false. As a result, some

users think marijuana gives them a new understanding about life. Many people who try marijuana use

it only a few times or infrequently. However, others become dependent on the drug and have great

difficulty in stopping its use.


Marijuana has been used as a medicine and an intoxicant for thousand of years in many parts

of the world. In the United States, marijuana use has been prohibited by state and local laws since the

early 1900's, and by federal law since 1937. In spite of these laws, use of the drug became widespread

during the 1960's and 70's, especially among young people. Between 1969 and 78, the federal and

many state governments reduced the criminal charge for possession of small amounts of marijuana

from a felony to a misdemeanor. Some states even substituted fines for jail sentences. Surveys

indicated a decline in marijuana