What is Marijuana and why is it used?

Marijuana is a mind-altering psychoactive drug made from the Cannabis Sativa plant. THC (delta-9-tetrahydrocannabinol) is the main chemical ingredient that produces the psychoactive effect people feel when using marijuana.  Although THC can be found in all parts of the cannabis sativa plant, it is highly concentrated in the plant’s flower also known as the bud.



What is CBD?

CBD or Cannabidiol, is believed to be responsible for the medicinal quality of marijuana and does not cause a psychoactive effect like THC. The only CBD products that have been approved by the Food and Drug Administration is a prescription oil called Epidiolex used to treat two types of Epilepsy. CBD is being studied as a possible treatment for a wide range of conditions including Parkinson’s disease, schizophrenia, diabetes, multiple sclerosis and anxiety. 

Some known side effects of using CBD include dry mouth, diarrhea, reduced appetite, drowsiness and fatigue. CBD can also interact with other medications such as blood thinners.

The amount of CBD in the marijuana plant is generally very low. 


How much THC and CBD are in marijuana?

The United States Drug Enforcement Agency has tested samples of confiscated marijuana to determine how the concentration of THC and CBD have changed over time.  Since 1995, THC levels have gone up while at the same time CBD levels have gone down.  This is due to the genetic manipulation of the Cannabis Sativa plant by the cannabis growers. Higher THC values means marijuana’s psychoactive effects have increased while at the same time the lower CBD values have reduced marijuana’s medicinal effects.


Street Names

Aunt Mary, BC Bud, Chronic, Dope, Gangster, Ganja, Grass, Hash, Herb, Joint, Mary Jane, Mota, Pot, Reefer, Sinsemilla, Skunk, Smoke, Weed, Yerba


How is Marijuana used?

  • Smoked as a cigarette or in pipe or bong

  • Smoked in blunts (cigar emptied of tobacco and filled with marijuana, and sometimes mixed with additional drugs)

  • Mixed with food (edibles)

  • Brewed as tea


Short-Term Effects

When a person smokes marijuana, THC quickly passes from the lungs into the bloodstream. The blood 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, they generally feel the effects after 30 minutes to 1 hour.

THC acts on specific brain cell receptors that ordinarily react to natural THC-like chemicals. 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 people 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

  • hallucinations (when taken in high doses)

  • delusions (when taken in high doses)

  • psychosis (risk is highest with regular use of high potency marijuana)


Long-Term Effects

Marijuana also affects brain development. When people begin using marijuana as teenagers, the drug may impair thinking, memory, and learning functions and affect how the brain builds connections between the areas necessary for these functions. Researchers are still studying how long marijuana’s effects last and whether some changes may be permanent.

For example, a study from New Zealand conducted in part by researchers at Duke University showed that people who started smoking marijuana heavily in their teens and had an ongoing marijuana use disorder lost an average of 8 IQ points between ages 13 and 38. The lost mental abilities didn’t fully return in those who quit marijuana as adults. Those who started smoking marijuana as adults didn’t show notable IQ declines.


Physical Effects

  • Breathing problems. Marijuana smoke irritates the lungs, and people who smoke marijuana frequently can have the same breathing problems as those who smoke tobacco. These problems include daily cough and phlegm, more frequent lung illness, and a higher risk of lung infections. Researchers so far haven’t found a higher risk for lung cancer in people who smoke marijuana.8

  • 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.  Medical experts believe marijuana use during pregnancy is linked to lower birth weight and 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. Children exposed to marijuana in the womb have an increased risk of problems with attention, memory, and problem-solving compared to unexposed children. Some research also suggests that moderate amounts of THC are excreted into the breast milk of nursing mothers. With regular use, THC can reach amounts in breast milk that could affect the baby’s developing brain. Other recent research suggests an increased risk of preterm births.

  • Intense nausea and vomiting. Regular, long-term marijuana use can lead to some people to develop Cannabinoid Hyperemesis Syndrome. This causes users to experience regular cycles of severe nausea, vomiting, and dehydration, sometimes requiring emergency medical attention.


Mental Effects

  • Long-term marijuana use has been linked to mental illness in some people, such as:

  • temporary hallucinations

  • temporary paranoia

  • worsening symptoms in patients with schizophrenia—a severe mental disorder with symptoms such as hallucinations, paranoia, and disorganized thinking

  • Marijuana use has also been linked to other mental health problems, such as depression, anxiety, and suicidal thoughts among teens. However, study findings have been mixed.


Is marijuana addictive?

Marijuana use can lead to the development of a substance use disorder, a medical illness in which the person is unable to stop using even though it’s causing health and social problems in their life. Severe substance use disorders are also known as addiction. Research suggests that between 9 and 30 percent of those who use marijuana may develop some degree of marijuana use disorder. People who begin using marijuana before age 18 are four to seven times more likely than adults to develop a marijuana use disorder.

Many people who use marijuana long term and are trying to quit report mild withdrawal symptoms that make quitting difficult. These include:

  • grouchiness

  • sleeplessness

  • decreased appetite

  • anxiety

  • cravings


 What treatments are available for marijuana use disorder?

No medications are currently available to treat marijuana use disorder, but behavioral support has been shown to be effective. Examples include therapy and motivational incentives (providing rewards to patients who remain drug-free). Continuing research may lead to new medications that help ease withdrawal symptoms, block the effects of marijuana, and prevent relapse.


Driving Under the Influence of Marijuana

Marijuana is unsafe if you are behind the wheel. In general, teen drivers are less experienced and more likely to react poorly in risky situations than older drivers. They are more likely to drive recklessly, speeding and allowing less distance between vehicles. When you pair inexperience with marijuana use, the results can be dangerous. Research shows that marijuana effects safe-driving skills, like judgment, coordination, and reaction time. Marijuana makes it hard to judge distances and react to signals and sounds on the road. As with any psychoactive drug, impaired driving can cause deadly vehicle crashes.


Effect on School Performance

Marijuana is linked to problems in school. Marijuana dulls your attention, memory, and learning skills. These effects can last for days and sometimes weeks, depending on how often you use marijuana. Compared with teens who don’t use, students who use marijuana are more likely not to finish high school or get a college degree.5 Marijuana also affects timing, movement, and coordination, which can harm athletic performance


Mental Illness Link

Marijuana use has been linked to an increased chance for mental illness. In addition to addiction, marijuana use is linked with a higher risk for schizophrenia, depression, and anxiety. It’s not clear if marijuana use actually causes these conditions, but research shows a connection. The amount of drug used, the age at first use, and a person’s genes influence this relationship


Marijuana Use by Teens

Past month, past year and lifetime marijuana use remained steady among 8th, 10th, and 12th graders. This year, 6.6 percent of 8th, 18.4 percent of 10th, and 22.3 percent of 12th graders reported past month marijuana use while 11.8, 28.8, and 35.7 of respective 8th, 10th and 12th graders reported past year use. When asked about how teens are consuming marijuana, 86.4 percent say they smoke it.

Daily marijuana use, however, increased among 8th and 10th graders. Daily use is defined as use on 20 or more occasions in the past 30 days and was reported by 1.3 percent of 8th graders, 4.8 percent of 10th graders and 6.4 percent of 12th graders. While these percentages may seem low, they represent an increase of 85.7 percent among 8th graders and 41.2 percent among 10th graders, compared to 2018. The percentage of teens who think that regular use of marijuana is risky has been trending down since the mid-2000’s. In 2019, 52.3 percent of 8th graders, 39.6 percent of 10th graders and 30.3 percent of 12th graders perceived great harm from regular marijuana smoking. Despite the expansion of state medical marijuana laws, the perception of availability did not change in the past year and long-term trends suggest a gradual decline in the percent of teens saying marijuana is easy to get.