What is marijuana?
Marijuana refers to the dried leaves, flowers, stems, and seeds from the Cannabis sativa or Cannabis indicaplant. The plant contains the mind-altering chemical THC and other similar compounds. Extracts can also be made from the cannabis plant.
Marijuana is the most commonly used illicit drug in the United States. Its use is widespread among young people. In 2015, more than 11 million young adults ages 18 to 25 used marijuana in the past year. According to the Monitoring the Future survey, rates of marijuana use among middle and high school students have dropped or leveled off in the past few years after several years of increase. However, the number of young people who believe regular marijuana use is risky is decreasing.
Legalization of marijuana for medical use or adult recreational use in a growing number of states may affect these views.
How do people use marijuana?
People smoke marijuana in hand-rolled cigarettes (joints) or 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, some 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. Some vaporizers use a liquid marijuana extract.
People can mix marijuana 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.
How does marijuana affect the brain?
Marijuana has both short-and long-term effects on the brain.
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 overactivates 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
hallucinations (when taken in high doses)
delusions (when taken in high doses)
psychosis (when taken in high doses)
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.
What are the other health effects of marijuana?
Marijuana use may have a wide range of effects, both physical and mental.
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.
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. One study found that about 20% of pregnant women 24-years-old and younger screened positive for marijuana. However, this study also found that women were about twice as likely to screen positive for marijuana use via a drug test than they state in self-reported measures.This suggests that self-reported rates of marijuana use in pregnant females is not an accurate measure of marijuana use and may be underreporting their use. Additionally, in one study of dispensaries, nonmedical personnel at marijuana dispensaries were recommending marijuana to pregnant women for nausea, but medical experts warn against it. This concerns medical experts because 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. More research is needed. Read our Marijuana Research Report for more information about marijuana and pregnancy.
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.
Long-term marijuana use has been linked to mental illness in some people, such as:
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.
Are there effects of inhaling secondhand marijuana smoke?
Failing a Drug Test?
While it's possible to fail a drug test after inhaling secondhand marijuana smoke, it's unlikely. Studies show that very little THC is released in the air when a person exhales. Research findings suggest that, unless people are in an enclosed room, breathing in lots of smoke for hours at close range, they aren't likely to fail a drug test.Even if some THC was found in the blood, it wouldn't be enough to fail a test.
Getting high from passive exposure?
Similarly, it's unlikely that secondhand marijuana smoke would give nonsmoking people in a confined space a high from passive exposure. Studies have shown that people who don't use marijuana report only mild effects of the drug from a nearby smoker, under extreme conditions (breathing in lots of marijuana smoke for hours in an enclosed room).
Other Health Effects?
More research is needed to know if secondhand marijuana smoke has similar health risks as secondhand tobacco smoke. A recent study on rats suggests that secondhand marijuana smoke can do as much damage to the heart and blood vessels as secondhand tobacco smoke.But researchers haven't fully explored the effect of secondhand marijuana smoke on humans. What they do know is that the toxins and tar found in marijuana smoke could affect vulnerable people, such as children or people with asthma.
How Does Marijuana Affect a Person's Life?
Compared to those who don't use marijuana, those who frequently use large amounts report the following:
People also report less academic and career success. For example, marijuana use is linked to a higher likelihood of dropping out of school. It's also linked to more job absences, accidents, and injuries.
Is marijuana a gateway drug?
Use of alcohol, tobacco, and marijuana are likely to come before use of other drugs.Animal studies have shown that early exposure to addictive substances, including THC, may change how the brain responds to other drugs. For example, when rodents are repeatedly exposed to THC when they're young, they later show an enhanced response to other addictive substances—such as morphine or nicotine—in the areas of the brain that control reward, and they're more likely to show addiction-like behaviors.
Although these findings support the idea of marijuana as a "gateway drug," the majority of people who use marijuana don't go on to use other "harder" drugs. It's also important to note that other factors besides biological mechanisms, such as a person’s social environment, are also critical in a person’s risk for drug use and addiction.
Can a person overdose on marijuana?
An overdose occurs when a person uses enough of the drug to produce life-threatening symptoms or death. There are no reports of teens or adults dying from marijuana alone. However, some people who use marijuana can feel some very uncomfortable side effects, especially when using marijuana products with high THC levels. People have reported symptoms such as anxiety and paranoia, and in rare cases, an extreme psychotic reaction (which can include delusions and hallucinations) that can lead them to seek treatment in an emergency room.
While a psychotic reaction can occur following any method of use, emergency room responders have seen an increasing number of cases involving marijuana edibles. Some people (especially preteens and teens) who know very little about edibles don't realize that it takes longer for the body to feel marijuana’s effects when eaten rather than smoked. So they consume more of the edible, trying to get high faster or thinking they haven't taken enough. In addition, some babies and toddlers have been seriously ill after ingesting marijuana or marijuana edibles left around the house.
Impact on Workplace Safety and Productivity
Safety concerns are often a company's primary reason for prohibiting marijuana in the workplace, and they are a valid basis for banning the drug. Marijuana use has been linked to an increase in job accidents and injuries, and the National Institute on Drug Abuse notes that the short-term effects of marijuana include impaired body movement, difficulty with thinking and problem-solving, memory problems, and an altered sense of time.
In May 2015, an article in the Journal of Occupational and Environmental Medicine concluded that there is a likely statistical association between illicit drug use, including marijuana, and workplace accidents. While some studies suggest that marijuana use may be reasonably safe in some controlled environments, its association with workplace accidents and injuries raises concern.
The impact marijuana use makes on transportation safety can be especially alarming. The drug impairs attentiveness, motor coordination, and reaction time and impacts the perception of time and speed. Studies from the National Institute on Drug Abuse have found that marijuana negatively impacts driving performance, and other researchers have found that acute use of the drug increases the risk of crashes and fatal collisions.
How are tests conducted?
Tests are mainly conducted by specialist, external agencies.For most workplaces that test employees, testing isundertaken at frequent intervals, with candidates for testingselected randomly. This random selection means that any employee could be tested, so anyone who has used drugs is at risk of being caught.
Tests are generally undertaken in the form of saliva or urine tests. For a saliva test, after filling in the required paperwork, a candidate will be asked to run a swab down the inside of their mouth to collect saliva. The swab will immediately be stored and labelled and the candidate will often be asked to sign off that the sample is theirs.
For a urine test, a candidate will be asked to provide a sample in a supplied container. Procedures are usually put in place to ensure tests can’t be faked, with candidates generally not allowed to flush or wash their hands until the sample is safely in the testing agent’s hands. Once testing is complete for the day, the testing agent will take the samples with them, and will then inform the employer and relevant employee of any positive results. If you have used a drug like cannabis prior to your drug test, those days of waiting can be very nerve-racking!
Also worth keeping in mind, especially if you drive for a living, is that police in each state and territory are now conducting roadside drug tests. These saliva tests indicate use of many of the drugs mentioned, including cannabis, and can mean you risk losing both your job and your licence if you get a positive reading.