Marijuana (grass, pot, weed) is the common name for a crude drug made from the plant Cannabis sativa. The main mind-altering (psychoactive) ingredient in marijuana is THC (delta-9-tetrahydrocannabinol), but more than 400 other chemicals also are in the plant. A marijuana “joint” (cigarette) is made from the dried particles of the plant. The amount of THC in the marijuana determines how strong its effects will be. The type of plant, the weather, the soil, the time of harvest, and other factors determine the strength of marijuana.
The strength of today’s marijuana is as much as ten times greater than the marijuana used in the early 1970s. This more potent marijuana increases physical and mental effects and the possibility of health problems for the user. Hashish, or hash, is made by taking the resin from the leaves and flowers of the marijuana plant and pressing it into cakes or slabs. Hash is usually stronger than crude marijuana and may contain five to ten times as much THC. Pure THC is almost never available, except for research. Substances sold as THC on the street often turn out to be something else, such as PCP.
Some immediate physical effects of marijuana include a faster heartbeat and pulse rate, bloodshot eyes, and a dry mouth and throat. No scientific evidence indicates that marijuana improves hearing, eyesight, and skin sensitivity. Studies of marijuana’s mental effects show that the drug can impair or reduce short-term memory, alter sense of time, and reduce ability to do things which require concentration, swift reactions, and coordination, such as driving a car or operating machinery. Long-term regular users of marijuana may become psychologically dependent. They may have a hard time limiting their use, they may need more of the drug to get the same effect, and they may develop problems with their jobs and personal relationships. The drug can become the most important aspect of their lives.
One major concern about marijuana is its possible effects on young people as they grow up. Research shows that the earlier people start using drugs, the more likely they are to go on to experiment with other drugs. In addition, when young people start using marijuana regularly, they often lose interest and are not motivated to do their schoolwork. The effects of marijuana can interfere with learning by impairing thinking, reading comprehension, and verbal and mathematical skills. Research shows that students do not remember what they have learned when they are “high”.
Marijuana use increases the heart rate as much as 50 percent, depending on the amount of THC. It can cause chest pain in people who have a poor blood supply to the heart – and it produces these effects more rapidly than tobacco smoke does. Scientists believe that marijuana can be especially harmful to the lungs because users often inhale the unfiltered smoke deeply and hold it in their lungs as long as possible. Therefore, the smoke is in contact with lung tissues for long periods of time, which irritates the lungs and damages the way they work. Marijuana smoke contains some of the same ingredients in tobacco smoke that can cause emphysema and cancer. In addition, many marijuana users also smoke cigarettes; the combined effects of smoking these two substances creates an increased health risk.
Marijuana smoke has been found to contain more cancer-causing agents than is found in tobacco smoke. Examination of human lung tissue that had been exposed to marijuana smoke over a long period of time in a laboratory showed cellular changes called metaplasia that are considered precancerous. In laboratory test, the tars from marijuana smoke have produced tumors when applied to animal skin. These studies suggest that it is likely that marijuana may cause cancer if used for a number of years.
Marijuana is a very dangerous drug.