What Is Marijuana and Who Uses It?

Marijuana is the most widely used illegal drug in the United States. It is a dry, shredded green/brown mix of flowers, stems, seeds, and leaves of the plant Cannabis sativa. A stronger form of marijuana called hashish (hash) looks like brown or black cakes or balls. Street names for marijuana include pot, herb, weed, grass, Jane, reefer, dope, and ganja. Marijuana is typically smoked in cigarettes (joints or spliffs), hollowed-out cigars (blunts), pipes (bowls), or water pipes (bongs). Some people mix it into food or brew it as a tea.

What Are the Short-Term Effects of Marijuana?

The main active chemical in marijuana is THC (delta9tetrahydrocannabinol). When smoked, THC passes from the lungs into the bloodstream, which transports it to the brain and other organs. When it reaches the brain, THC connects with a certain type of receptor on nerve cells in areas that affect coordination, thought, memory, concentration, sensory and time perception, and pleasure. This causes the marijuana "high." Marijuana users can experience these short-term effects:
•distorted perception
•difficulty in thinking and problem solving
•problems with memory and learning
•loss of coordination

These changes in perception and coordination make activities like driving dangerous while under the influence of the drug. Approximately 38,000 U.S. high school seniors reported in 2001 that they crashed while driving under the influence of marijuana and 46,000 reported that they crashed while under the influence of alcohol. Smoking marijuana and then driving is similar to driving with a blood alcohol content of 0.07% to 0.10%, which is considered legally drunk in all 50 states.


Are There Any Long-Term Effects?

Research has found some of the side effects of persistent marijuana use are:

•Changes in the brain. Marijuana can affect the areas of the brain that play a part in response to stress, motivation, and reward.

•Fertility implications. Animal studies suggest that heavy users may experience disruptions in ovulation or produce less sperm.
This means that heavy users may have difficulty having children as they get older. Studies also show that babies born to women who use marijuana when they are pregnant may be more likely to have developmental and behavioral problems.

•Respiratory problems and other illnesses. Marijuana smoke has 50% to 70% more carcinogens (cancer-causing substances) than cigarette smoke does. Because users inhale more deeply and hold their breath longer with marijuana than cigarette smokers do, their lungs are exposed to these substances for longer periods of time. This is why people who smoke marijuana have more respiratory problems — such as having more mucus, chronic cough, and bronchitis (irritated breathing passages). They may also have an increased risk for neck, head, and lung cancers, and this risk rises with the amount smoked.

•Changes in blood pressure. Over time, continued use of marijuana can lead to decreased blood pressure, which may cause dizziness. It also seems to impair the body's ability to fight off infections and some other diseases.

•Emotional problems. Heavy users are more likely to report symptoms of depression than nonusers. They can also feel more anxiety, have more personality disturbances, and are at an increased risk of developing schizophrenia, a severe form of mental illness.

In addition to the long-term and short-term side effects, research is finding other potentially problematic aspects to marijuana use. One of these is marijuana's possible connection with other drug use. Although it is not certain that marijuana is the direct cause, people who have used marijuana are eight times more likely to have used cocaine, 15 times more likely to have used heroin, and five times more likely to develop a need for treatment for substance abuse. Finally, there are the legal aspects of marijuana use. Every state has laws against the growth, possession, and sale of marijuana. Penalties vary from state to state, but they usually involve fines and/or jail time for those caught using or distributing marijuana. Users may end up with criminal records that can hurt their future educational plans (such as college) and careers.