Also known as: Chronic, Grass, Herb, Mary Jane, Reefer, Skunk, Weed
Marijuana refers to the dried leaves, flowers, stems, and seeds from the hemp plant, Cannabis sativa. Marijuana contains the mind-altering chemical delta-9-tetrahydrocannabinol (THC) and other related compounds. Marijuana is the most commonly used illicit drug in the world. A survey conducted in 2007 found that 14.4 million individuals in the US alone had smoked marijuana at least once during the previous month.
How Marijuana is Used
Marijuana is usually smoked as a cigarette (joint). But many people smoke marijuana in pipes or water pipes (bongs). They also smoke it in blunts—emptied cigars that have been partly or completely refilled with marijuana. To avoid inhaling smoke, more people are using vaporizers. These devices pull the active ingredients (including THC) from the marijuana and collect their vapor in a storage unit. A person then inhales the vapor, not the smoke.
Marijuana can also be consumed in food (edibles), such as brownies, cookies, or candy, or brew it as a tea. A newly popular method of use is smoking or eating different forms of THC-rich resins.
When a person smokes a joint, he usually feels its effect within minutes. The immediate sensations — increased heart rate, lessened coordination and balance, and a “dreamy,” unreal state of mind — peak within the first 30 minutes. These short-term effects usually wear off in two to three hours, but they could last longer, depending on how much the user takes, the potency of THC and the presence of other drugs added into the mix.
As the typical user inhales more smoke and holds it longer than he would with a cigarette, a joint creates a severe impact on the lungs. Aside from the discomfort that goes with sore throats and chest colds, it has been found that consuming one joint gives as much exposure to cancer-producing chemicals as smoking five cigarettes.
Smoking THC-rich resins extracted from the marijuana plant is on the rise. Users call this practice dabbing. People are using various forms of these extracts, such as:
- hash oil or honey oil—a gooey liquid
- wax or budder—a soft solid with a texture like lip balm
- shatter—a hard, amber-colored solid
These extracts can deliver extremely large amounts of THC to users, and their use has sent some people to the emergency room. Another danger is in preparing these extracts, which usually involves butane (lighter fluid). A number of people who have used butane to make extracts at home have caused fires and explosions and have been seriously burned.
How Marijuana Affect the Brain
Marijuana has both short- and long-term effects on the brain. THC (in magenta) acts on numerous areas in the brain.
When a person smokes marijuana, THC quickly passes from the lungs into the bloodstream. The blood then carries the chemical to the brain and other organs throughout the body. The body absorbs THC more slowly when the person eats or drinks it. In that case, the user generally feels the effects after 30 minutes to 1 hour.
THC acts on specific brain cell receptors that ordinarily react to natural THC-like chemicals in the brain. These natural chemicals play a role in normal brain development and function.
Marijuana over-activates parts of the brain that contain the highest number of these receptors. This causes the “high” that users feel. Other effects include:
- altered senses (for example, seeing brighter colors)
- altered sense of time
- changes in mood
- impaired body movement
- difficulty with thinking and problem-solving
- impaired memory
Marijuana also affects brain development. When marijuana users begin using as teenagers, the drug may reduce thinking, memory, and learning functions and affect how the brain builds connections between the areas necessary for these functions.
Marijuana’s effects on these abilities may last a long time or even be permanent.
For example, a study showed that people who started smoking marijuana heavily in their teens and had an ongoing cannabis use disorder lost an average of eight IQ points between ages 13 and 38. The lost mental abilities did not fully return in those who quit marijuana as adults. Those who started smoking marijuana as adults did not show any notable IQ declines.
Physical Effects of Marijuana
- Breathing problems — Marijuana smoke irritates the lungs, and frequent marijuana smokers can have the same breathing problems that tobacco smokers have. These problems include daily cough and phlegm, more frequent lung illness, and a higher risk of lung infections. Researchers still do not know whether marijuana smokers have a higher risk for lung cancer.
- Increased heart rate — Marijuana raises heart rate for up to 3 hours after smoking. This effect may increase the chance of heart attack. Older people and those with heart problems may be at higher risk
- Problems with child development during and after pregnancy — Marijuana use during pregnancy is linked to increased risk of both brain and behavioral problems in babies. If a pregnant woman uses marijuana, the drug may affect certain developing parts of the fetus’s brain. Resulting challenges for the child may include problems with attention, memory, and problem-solving.