Globally, marijuana (cannabis) is the most commonly used illicit drug. Classified as a Schedule 1 controlled substance, marijuana is a mood-altering (psychoactive) drug that affects almost every organ in the body.
Surveys show that 34.9 percent of 12th graders in the United States use marijuana, and that close to 6 percent of 12th graders report daily use of the drug.
According to the 2013 National Survey on Drug Use and Health (NSDUH), 19.8 million adults in the U.S. used marijuana in the month prior to being surveyed, and 81 percent of current illicit drug users had used marijuana.
There is some evidence that Marijuana is useful for relieving severe pain, nausea, and other chronic conditions. However, there are also numerous health concerns.
Marijuana contains over 400 chemicals; THC (delta-9-tetrahydro-cannabinol) is the key psychoactive substance. The possible effects of marijuana include mood changes, suicidal thinking, and disruption to normal learning abilities. It may also be capable of producing dependency, psychosis, and addiction.
Fast facts on marijuana
Here are some key points about marijuana. More detail and supporting information is in the main article.
- The primary psychoactive ingredient in marijuana is delta-9-tetrahydro-cannabinol (THC)
- Cannabis contains more than 113 cannabinoids
- The effects of recreational cannabis use includes lightheadedness, a feeling of relaxation, increased appetite, and reduced blood pressure
What is marijuana?
Marijuana is derived from the Cannabis sativa plant and is sometimes used to treat chronic pain.
Marijuana is derived from the dried flowering tops, leaves, stems, and seeds of the Cannabis sativa (hemp) plant. Cannabis has been used for hundreds of years by humans, for fiber (hemp), seed oils, seed, medical treatment, and recreationally.
THC acts on specific brain cell receptors called cannabinoids.
Tests have shown THC has mild-to-moderate painkilling (analgesic) effects, and can be used for the treatment of pain. THC alters neurotransmitter release in the spinal cord, resulting in pain relief.
The compound is also known to stimulate appetite (informally known as "the munchies") and induce a relaxed state, as well as other effects on sense of smell, hearing, and eyesight. THC can also cause fatigue. In some people, THC may reduce aggression.
Some studies have shown that THC shows promise for the treatment of nausea and vomiting - it may have antiemetic qualities that make it helpful for people undergoing chemotherapy or other treatment where nausea can be a side effect.
Medical marijuana is used to treat chronic pain, muscle spasticity, anorexia, nausea, and sleep disturbances. Medical marijuana is not subject to governmental standardization, making its ingredients and potency unknown.
Marijuana can be smoked, inhaled through vapor, brewed as a tea, applied as a balm, or eaten in products such as brownies or chocolate bars.
Effects of marijuana
The effects of the more than 113 cannabinoids present in cannabis are largely unknown, but the most potent psychoactive agent identified to date is THC. When a person smokes cannabis, THC is quickly absorbed into the bloodstream, reaching the brain within minutes.
The body absorbs THC more slowly when it is eaten, delaying the onset of action for up to 2 hours and prolonging the duration of the effect.
THC and other cannabinoids in marijuana are similar to cannabinoids produced by the body. These natural cannabinoids act like neurotransmitters that send chemical messages between nerve cells (neurons) throughout the nervous system.
Neurotransmitters affect brain areas involved in memory, thinking, concentration, movement, coordination, sensory and time perception, as well as pleasure. The receptors that respond to these cannabinoids also respond to THC, which can alter and disrupt normal brain function.
THC has been shown to affect the hippocampus and orbitofrontal cortex - areas of the brain that control memory creation and attention. THC also disrupts the function of the cerebellum and basal ganglia, adversely affecting balance, posture, coordination, and reaction time, which can make it unsafe for a person using marijuana to drive a car, operate heavy machinery, or engage in sports or other potentially dangerous physical activities.
THC also stimulates certain cannabinoid receptors that increase the release of dopamine, a neurotransmitter related to feelings of pleasure. This effect, common to many drugs of misuse (including heroin, cocaine, amphetamine, and nicotine), may be the basis of its reinforcing properties and its recreational use. The effect is reversed by naloxone, suggesting an opioid link.
People use marijuana to achieve the feeling of elation (a high), giddiness, and relaxation. Marijuana also produces sensory perception changes; colors may seem brighter, music more vivid, and emotions more profound.
When cannabis is consumed for recreational purposes, the following effects are possible:
- Change in perception - marijuana can have slight hallucinogenic effects, making users see reality in a distorted way
- Alteration in mood - some may experience euphoria, become more animated, while others enter a state of relaxation
- Increased heart rate
- Reduction in blood pressure
- Impairment of concentration and memory
- Reduced psychomotor coordination
- Nausea (despite the fact that cannabis can treat the symptoms of nausea)
- Increase in appetite
- More rapid breathing
Depending on the length and amount of use, cannabis can still be detected in the urine for several months after its last use.
Potential hazards of marijuana
Individuals should never drive or operate heavy machinery while under the influence of marijuana as it impairs cognitive function and motor ability.
Below are some examples of studies and reports that suggest or demonstrate the negative consequences of cannabis consumption:
- You are significantly more likely to crash your car if you drive within 3 hours of smoking marijuana.
- Cannabis use might lead to male sexual dysfunction, according to a review of animal studies.
- Smoking marijuana could eventually suppress the body's immune system, making the user more susceptible to certain types of cancer and infections.
- Long-term marijuana use could increase the risk of developing psychosis.
- Gum disease risk - a study suggested that smoking cannabis raises the risk of developing gum disease, regardless of whether the user smokes tobacco.
- Reduced brain function - regular cannabis users who started before they were 15 years old scored worse on brain tests than their counterparts who started later in life, researchers found.
- Acute memory loss - smokers of potent cannabis strains may have a greater risk of acute memory loss. Skunk is an example of such a cannabis strain.
- Alters human DNA - a British study found compelling evidence that cannabis smoke damages human DNA in such a way that the user could become more susceptible to developing cancer.
- Testicular cancer - males who use marijuana frequently or long-term may have a considerably higher risk of developing testicular cancer, researchers at Fred Hutchinson Cancer Research Center found.
Marijuana dependency and addiction
Cannabis, like other analgesics, can cause dependence and addiction. Over time, the persistent overstimulation of the endocannabinoid system can cause changes in the brain that result in addiction; this is much more likely in people who start using marijuana when young and who are heavy users.
An estimated 9 percent of people who use marijuana become dependent on the drug. Teenage users have a 17 percent risk of becoming addicted, and 25-50 percent of regular (daily) users become addicted. Abrupt withdrawal from cannabis can be uncomfortable but not life-threatening.
The withdrawal syndrome begins on the second day of stopping and may persist for 2 weeks. Discontinuation symptoms include anxiety, irritability, insomnia, stomach pain, and decreased appetite. Sleep problems can potentially persist beyond that time frame.
It is important to note that "synthetic marijuana" is not actually marijuana, with some people being misled into trying K2/Spice (an untested and illegal synthetic cannabinoid).
The full extent of long-term health risks of chronic cannabis use is currently unknown. There is no determining who will develop serious physical, psychological, or other unwanted reactions.
As of January 31, 2014, the National Institute on Drug Abuse (NIDA) had 28 active research grants related to marijuana, investigating its effects in six different disease areas. These include autoimmune disease, inflammation, pain, seizure disorders, psychiatric disorders and substance use disorders, withdrawal, and dependence.
Some studies do show specific benefits of certain types of marijuana use, with the U.S. Food and Drug Administration (FDA) currently having approved certain THC-based medications for increasing appetite and reducing nausea.
THC may also decrease pain, inflammation, and muscle control problems, but medications have not yet been approved for these conditions.
Many researchers are investigating the medicinal potential of cannabidiol, a cannabinoid found in marijuana that does not have psychoactive effects. This drug may be helpful in relieving pain and inflammation, controlling epileptic seizures, and possibly for the treatment of mental illness and addictions.
Other researchers are looking at the potential for marijuana extracts to target and kill cancer cells, in particular as an adjunct treatment with radiation therapy.