Marijuana Information
Marijuana is a green or gray mixture of dried, shredded flowers and leaves of the hemp plant Cannabis sativa. There are over 200 slang terms for marijuana including "pot," "herb," "weed," "boom," "Mary Jane," "gangster," and "chronic." It is usually smoked as a cigarette (called a joint or a nail) or in a pipe or bong. In recent years, it has appeared in blunts. These are cigars that have been emptied of tobacco and re-filled with marijuana, often in combination with another drug, such as crack. Some users also mix marijuana into foods or use it to brew tea.
Marijuana's active chemical ingredient
The main active chemical in marijuana is THC (delta-9-tetrahydrocannabinol). In 1988, it was discovered that the membranes of certain nerve cells contain protein receptors that bind 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. The short-term effects of marijuana use include problems with memory and learning; distorted perception; difficulty in thinking and problem solving; loss of coordination; and increased heart rate, anxiety, and panic attacks.
Marijuana effects may be hereditary
Scientists have found that whether an individual has positive or negative sensations after smoking marijuana can be influenced by heredity. A recent study demonstrated that identical male twins were more likely than nonidentical male twins to report similar responses to marijuana use, indicating a genetic basis for their sensations. Identical twins share all of their genes, and fraternal twins share about half.
Environmental factors such as the availability of marijuana, expectations about how the drug would affect them, the influence of friends and social contacts, and other factors that would be different even for identical twins also were found to have an important effect; however, it also was discovered that the twins' shared or family environment before age 18 had no detectable influence on their response to marijuana.
Extent of Marijuana Use
Marijuana and the Monitoring the Future Study (MTF)
The NIDA-funded MTF provides an annual assessment of drug use among 12th, 10th, and 8th grade students and young adults nationwide. After decreasing for over a decade, marijuana use among students began to increase in the early 1990s. From 1996 to 1997, use of marijuana at least once (lifetime use) increased among 12th and 10th graders, continuing the trend seen in recent years. The seniors' rate of lifetime marijuana use is higher than any year since 1987, but all rates remain well below those seen in the late 1970s and early 1980s.
Past year and past month marijuana use did not change significantly from 1996 to 1997 in any of the three grades, suggesting the sharp increases of recent years may be slowing. Daily marijuana use in the past month increased among 12th graders, but decreased among 8th graders; this pattern of increases among older students and stable or declining rates among younger students was found with several indicators in the 1997 MTF.
Percentage of 8th-Graders Who Have Used Marijuana: Monitoring the Future Study
| 1991 | 1992 | 1993 | 1994 | 1995 | 1996 | 1997 | |
|---|---|---|---|---|---|---|---|
| Ever Used | 10.2% | 11.2% | 12.6% | 16.7% | 19.9% | 23.1% | 22.6% |
| Used in Past Year | 6.2 | 7.2 | 9.2 | 13.0 | 15.8 | 18.3 | 17.7 |
| Used in Past Month | 3.2 | 3.7 | 5.1 | 7.8 | 9.1 | 11.3 | 10.2 |
| Daily Use in Past Month | 0.2 | 0.2 | 0.4 | 0.7 | 0.8 | 1.5 | 1.1 |
Study shows an increase in all categories for six years with a slight reduction in ther seventh year.
Percentage of 12th-Graders Who Have Used Marijuana: Monitoring the Future Study
| 1979 | 1985 | 1991 | 1992 | 1993 | 1994 | 1995 | 1996 | 1997 | |
|---|---|---|---|---|---|---|---|---|---|
| Ever Used | 60.4% | 54.2% | 36.7% | 32.6% | 35.3% | 38.2% | 41.7% | 44.9% | 49.6% |
| Used in Past Year | 50.8% | 40.6% | 23.9% | 21.9% | 26.0% | 30.7% | 34.7% | 35.8% | 38.5% |
| Used in Past Month | 36.5% | 25.7% | 13.8% | 11.9% | 15.5% | 19.0% | 21.2% | 21.9% | 23.7% |
| Daily Use in Past Month | 10.3% | 4.9% | 2.0% | 1.9% | 2.4% | 3.6% | 4.6% | 4.9% | 5.8% |
Study shows a gradual reduction from 1979 to the early 1990s for most categories, then an increase from 1993 to 1997.
Marijuana and the Community Epidemiology Work Group (CEWG)
The resurgence in marijuana use continues, especially among adolescents, with rates of emergency department mentions of marijuana increasing from 1994 to 1995 in 10 cities, the percentage of treatment admissions increasing in 13 areas, and the National Institute of Justice's Drug Use Forecasting (DUF) percentages increasing among juvenile arrests at numerous sites. In several cities, such as Minneapolis/St. Paul, increasing treatment figures have been particularly notable among juveniles. Two factors may be contributing to the dramatic leap in adverse consequences: higher potency and the use of marijuana mixed with or in combination with other dangerous drugs.
Marijuana and the National Household Survey on Drug Abuse (NHSDA)
Marijuana remains the most commonly used illicit drug in the United States. There were an estimated 2.4 million people who started using marijuana in 1995. According to data from the 1996 NHSDA, more than 68.6 million Americans (32 percent) 12 years of age and older have tried marijuana at least once in their lifetimes, and almost 18.4 million (8.6 percent) had used marijuana in the past year. In 1985, 56.5 million Americans (29.4 percent) had tried marijuana at least once in their lifetimes, and 26.1 million (13.6 percent) had used marijuana within the past year.
Information on this page courtesy of National Institute on Drug Abuse.