Marijuana, or cannabis, is the most commonly used, federally illegal, substance in the United States with 48.2 million people, or 18% of Americans, reporting to have used it at least once in the year 2019 alone.
Recent research according to the Centers for Disease Control and Prevention (CDC) estimated that approximately 3 in 10 adults who use marijuana can become addicted, with the risk greatly increasing when looking at individuals who use marijuana before the age of 18.
In 2015, 4 million people in the U.S. met the diagnostic criteria for marijuana or cannabis use disorder according to a research report published by the National Institute on Drug Abuse (NIDA).
Despite its popularity and common use, there are many risks and dangers to marijuana, with regular use potentially causing marijuana dependence or marijuana use disorder.
Marijuana (Cannabis) – also known as weed, herb, grass, ganja, bud, Mary Jane, and many other names – is a mixture of the dried flowers of the Cannabis sativa plant.
According to SAMHSA (Substance Abuse and Mental Health Services Administration), more descriptively, marijuana refers to the dried leaves, stems, and seeds (and flowers) from the Cannabis sativa or Cannabis indica plant. Marijuana may be smoked in hand-rolled cigarettes, blunts, pipes, or through vaporizers that pull THC from the marijuana. Marijuana or cannabis can also be found mixed into foods such as brownies, cookies, and gummy candies and can even be brewed as a tea.
Even though many states have legalized the use of marijuana and THC, these substances remain illegal at the federal level.
The main psychoactive chemical in marijuana is delta-9-tetrahydrocannabinol (THC). This chemical is responsible for most of the intoxicating (and mind-altering) effects people experience, and may even seek, when using marijuana. THC can also be found in the resin produced by the leaves and buds primarily of the female cannabis plant. The plant contains more than 500 other chemicals in addition to THC, 100 of which are chemically related to THC and called cannabinoids.
After tobacco and alcohol, marijuana is the most commonly used addictive drug. In 2018 more than 11.8 million young adults had used marijuana in the past year.
According to NIDA when marijuana is smoked, THC and other chemicals in the plant pass from the lungs into the bloodstream which rapidly carries them throughout the body and to the brain.
While some may experience what is described to be a pleasant euphoria other common effects may vary dramatically depending on the person.
When consumed in foods and beverages, however, these effects are slightly delayed due to the drug needing to first pass through the digestive system. Because of this, eating or drinking marijuana typically delivers significantly less THC into the bloodstream than smoking an equivalent of the plant. This causes some to inadvertently consume more THC than they intend to lead to adverse effects.
Effects of THC from large doses of marijuana may lead to are:
For people who have taken large doses of marijuana, or where the marijuana has an unexpectedly high potency, an acute psychosis may occur which includes hallucinations, delusions, and a loss of sense of personal identity. Noticeable effects of smoked marijuana can generally last from 1 to 3 hours and when consumed in food or drink it may last for many hours. Detectable amounts of THC may remain in the body for days or even weeks after use.
As noted above, when someone smokes marijuana, the THC passes quickly from the lungs into the bloodstream. From the blood, the THC is carried to other parts of the body. THC affects specific brain receptors (cannabinoid receptors) that play a significant role in normal brain development and function.
Immediate (acute) effects of cannabis may be both positive and negative, ranging from pain relief and reduced anxiety to rapid heartbeat and paranoia.
Marijuana in particular activates the areas of the brain that contains the highest number of these receptors. When activated, the effects lead to the “high” many people experience.
Other effects include:
In the longer term, marijuana affects the brain’s overall development. The younger a person is when they begin using marijuana, the greater the risk of impaired thinking, memory, and impact on learning functions they have. This is due to the fact that the drug affects how the brain builds connections between the areas necessary for these functions.
There is still research being developed on how long marijuana’s effects may last and whether some of these changes may be permanent. One study from New Zealand by researchers at Duke University reported that people who began smoking marijuana heavily in their teens, and had an ongoing marijuana use disorder (MUD), lost an average of 8 IQ points between the ages 13 and 38. The study further reported that those who lost mental abilities did not see a recovery of those mental abilities after quitting marijuana use as adults. Conversely, those who began smoking marijuana as adults did not demonstrate notable declines in IQ.
Marijuana use has also been linked to mental illness in some such as:
In addition to this, it has also been linked to depression, anxiety, and suicidal thoughts among teens.
There are various other health effects that marijuana use may have on individuals including both physical and mental.
These physical effects of marijuana use include:
Substantial evidence from animal research and a number of studies in humans indicate that exposure to marijuana during development can cause long-term and possibly permanent adverse changes in the brain. Clinical studies found that cognitive impairments in adult rats exposed to THC during adolescence are associated with structural and functional changes in the hippocampus – the part of the brain responsible for learning and memory formation.
Long-term marijuana use has been linked to:
Researchers still do not yet know the full extent of the consequences marijuana has on the body and developing brain when an individual is exposed to high concentrations of THC. It is also difficult to determine whether the increase in the emergency department (ED) visits by people who test positive for marijuana use is related to the rise in the potency of marijuana (average THC content in confiscated marijuana samples in 1990 was 4%, it went up to 15% in 2018).
Ultimately, research regarding marijuana’s impact on brain structure in humans has produced conflicting results. While some studies suggest regular use in adolescence is associated with altered brain connectivity and reduced volume of brain regions compared to those who do not use, other studies have not found significant structural differences between the brains of those who do and do not use the drug.
According to Yale Medicine, about 10% of people who begin smoking cannabis will become addicted and 30% of current users meet the criteria for addiction. Chronic marijuana use can lead to the development of marijuana use disorder (MUD) which takes the form of addiction in severe cases. Marijuana use disorder becomes an addiction when someone cannot stop using the drug even when it negatively impacts various aspects of their life. It is possible to be dependent on marijuana without being addicted, and because of this, estimates of the number of people addicted to marijuana are controversial.
The risk of developing marijuana use disorder is higher in those who begin using marijuana during adolescence, or younger than 18 years of age, and in those who use marijuana more frequently. According to NIDA in 2015, about 4 million people in the U.S. met the diagnostic criteria for marijuana use disorder, and 138,000 voluntarily sought treatment for their marijuana use.
Marijuana use can lead to the development of problem use, known as marijuana use disorder (MUD) or cannabis use disorder (CUD). In severe cases, both disorders can take the form of addiction. According to the National Institute on Drug Abuse (NIDA), 30% of those who use marijuana may have some degree of marijuana use disorder. Additionally, people who began using marijuana before the age of 18 were found to be 4 to 7 times more likely to develop MUD than adults.
The American Psychiatric Association’s most recent criteria for substance use disorders include tools to identify marijuana (cannabis) addiction and for someone to be considered addicted they must meet at least 2 of the 11 criteria provided. Criteria included on this list are an inability to stop or reduce consumption, frequent cravings, and issues with socializing and relationships.
Some genetic studies suggest there may be a link between addiction to cannabis and hereditary factors that might contribute to marijuana dependence however more research is needed to confirm findings.
Those struggling with marijuana use disorder may feel symptoms of withdrawal when they stop using the drug. This is because of the level of dependence their body has developed to the substance.
Dependence is considered when a person feels or displays withdrawal symptoms when they are not taking the drug. It is characterized by the brain adapting to large amounts of the drug by reducing the production of and sensitivity to its endocannabinoid neurotransmitters. Those who use marijuana or struggle with marijuana dependency frequently report the following withdrawal symptoms within the first week of quitting:
These symptoms may last up to 2 weeks.
According to the CDC, the following are signs of marijuana use disorder (MUD):
Because some people who struggle with marijuana use disorder may need to increase their marijuana dosage over time to experience a “high”, their brain is at a greater risk of adverse THC (tetrahydrocannabinol) effects.
Researchers have not yet concluded the full extent of the consequences of the body’s exposure to high concentrations of THC or whether the recent increases in concentrations affect the risk of someone developing MUD.
According to NIDA, research has shown that marijuana’s negative effects on learning, attention, and memory can last long after the acute effects of the drug wear off. In a review of 48 relevant studies, researchers found marijuana use to be associated with reduced educational performance and chances of graduating. An analysis of three studies in Australia and New Zealand found that younger people who used marijuana regularly were significantly less likely than their non-using peers to finish high school or obtain a degree.
Other studies have revealed a link between heavy marijuana use and the following:
In the workplace, there have been studies that have suggested links between marijuana use and increased risk for injury or accidents. One study revealed that postal workers who tested positive for marijuana on pre-employment drug tests (urine) had 55% more industrial accidents, 85% more injuries and 75% greater absenteeism compared with those who tested negative for marijuana use.
According to Yale Medicine, behavioral therapies may help to treat marijuana (cannabis) addiction. Cognitive behavioral therapy in particular helps to identify and modify damaging thinking and behavior and can play a positive role in helping those overcome their struggle with addiction. There are not currently any FDA-approved medications for the treatment of marijuana use disorder and according to Yale Medicine psychiatrist Deepak Cyril D’Souza, MD, drugs to lessen marijuana cravings have often proved to be unsuccessful. He also highlights that there is an urgent need to develop more effective behavioral or pharmacological treatment options for cannabis use disorder.
On average, according to NIDA, adults seeking treatment for marijuana use disorders have used marijuana nearly every day for more than 10 years and have attempted to quit more than six times. NIDA highlights the following behavioral treatments to be effective:
To learn more about marijuana addiction and treatment options available for marijuana use disorder, reach out to our admissions team today.
NIH, National Institute on Drug Abuse–Is marijuana addictive? , References, How does marijuana use affect school, work, and social life?
Substance Abuse and Mental Health Services Administration–Know the Risks of Marijuana