When marijuana is smoked, THC passes rapidly from the lungs into the bloodstream, which carries the substance to the brain and other organs throughout the body. THC is absorbed more slowly when ingested through food or drink.
Regardless of how THC is ingested, the substance acts specifically on the brain cell’s cannabinoid receptors. These receptors—ordinarily activated by THC-like chemicals produced naturally by the body—are part of the neural communication network, called the endocannabinoid system, which plays an important role in normal brain development and function.
The highest density of cannabinoid receptors is found in parts of the brain that influence pleasure, memory, thinking, concentration, sensory and time perception, and coordinated movement. Marijuana over-activates the endocannabinoid system, causing the “high” and other effects that users experience, such as:
· Altered perceptions and mood
· Impaired coordination
· Difficulty with thinking and problem solving
· Disrupted learning and difficulty recollecting memories
· Decreased appetite
Research indicates that using marijuana can cause or exacerbate problems in daily life. Heavy users tend to report lower life satisfaction, poorer mental and physical health, more relationship problems and less academic or career success when compared with non-using peers. Use of the drug is also associated with a higher likelihood of dropping out of school. Several workplace studies associate marijuana use with increased absences, tardiness, accidents, workers’ compensation claims and job turnover.
Marijuana use is associated with a range of health issues, particularly related to heart and lung problems and mental health conditions.
Marijuana smoke is an irritant to the lungs, and frequent smokers can experience many of the same respiratory problems experienced by tobacco smokers, such as:
· Daily cough and phlegm production
· Frequent acute chest illness
· Heightened risk of lung infections
· Damage to the immune system
· Kills brain cells and damages central nervous system
· Fertility issues
· Increased heart rate and blood pressure
One study found that people who smoke marijuana frequently but do not smoke tobacco have more health problems and miss more days of work than those who don’t smoke marijuana, mainly due to respiratory illnesses. It is not yet known whether marijuana smoking contributes to the risk for lung cancer.
Research also indicates that use raises the heart rate by 20-100 percent shortly after smoking; this effect can last up to three hours. One study found that marijuana smokers have a 4.8-fold increase in the risk of heart attack in the first hour after using the substance. The risk may be even greater for older adults and those with cardiac vulnerabilities.
Several studies link chronic marijuana use and mental illness. High doses can produce a temporary psychotic reaction in some users. Use of the drug can also worsen the course of illness for patients who have schizophrenia. A series of large, longitudinal studies also shows a link between marijuana and the development of psychosis.
Marijuana abuse has also been associated with other mental health problems, such as:
· Personality disturbances
· Suicidal thoughts (among adolescents)
· Lack of motivation to engage in typically rewarding activities
More research is needed to better understand these mental health links and ramifications. Using marijuana during pregnancy is associated with increased risk of neurobehavioral problems in babies. Because THC and other compounds mimic the body’s own endocannabinoid chemicals, marijuana use by pregnant mothers may alter the developing endocannabinoid system in the brain of the fetus. Consequences for the child can include difficulties related to attention, memory and problem solving.
Marijuana has also been shown to negatively affect the brain development of young people who are heavy users. The effects on thinking and memory may last a long time or even be permanent. A study of individuals who began using the drug in adolescence revealed substantially reduced connectivity in areas of the brain responsible for learning and memory. A long-term study in New Zealand showed that people who began smoking the drug heavily in their teens lost an average of eight points in IQ between ages 13-38. The lost cognitive abilities were not fully restored in those who quit smoking marijuana as adults. Those who started smoking the drug in adulthood did not show significant IQ declines.
Additionally, because it impairs judgment and motor coordination, marijuana use contributes to a greater risk of injury or death while driving a car. Data analysis suggests that marijuana use more than doubles a driver’s risk of being in an accident. On a related note, the combination of marijuana and alcohol increases driving impairment more than either substance alone.
Contrary to common belief, marijuana is an addictive substance. Research suggests that approximately nine percent of users develop addiction. The estimated incidence of addiction increases among those who start using at a young age (an estimated 17 percent develop addiction) and among people who use the drug daily (an estimated 25-50 percent become addicted).
Individuals who are addicted to cannabis may experience symptoms of withdrawal when attempting to stop using the drug. Long-term users who try to quit report withdrawal symptoms such as irritability, sleeplessness, decreased appetite, anxiety, and drug craving–all of which can make it difficult to abstain. Behavioral interventions, including cognitive-behavioral therapy and motivational incentives (e.g., providing vouchers for goods or services to patients who remain abstinent) have proven effective in treatment and rehab for marijuana addiction. Although medications to address marijuana/cannabis addiction are not currently available, recent discoveries about the endocannabinoid system offer promise in developing medications to ease withdrawal symptoms, block the drug’s intoxicating effects, and prevent relapse.
Addiction to marijuana is most diagnosed during adolescence or young adulthood. However, recent trends toward greater societal acceptance of marijuana use and increased availability of both recreational and medical forms of the drug may increase the addiction rate in older adults. As with other types of drug addiction, there are behavioral and physical signs that can signal marijuana addiction (known medically as cannabis use disorder).
Behavioral changes include:
· Distorted perceptions
· Impaired coordination
· Difficulty in thinking and problem solving
· Ongoing problems with learning and memory
Other signs of marijuana abuse, misuse and addiction include:
· Red, blurry, bloodshot eye
· Constant, mucus-filled cough
· Rapid heartbeat
· Dry mouth
· Anxiety, paranoia, or fear
· Poor memory
· Poor coordination
· Slow reaction time
· Loss of control
Long-term drug abuse is associated with several symptoms of marijuana withdrawal, which typically develop within one week of discontinuing use. Some of the most common symptoms of cannabis withdrawal include:
· Irritability, anger, or aggression
· Nervousness or anxiety
· Sleep difficulty
· Decreased appetite or weight loss
· Depressed mood
· Physical symptoms such as abdominal pain, shakiness/tremors, sweating, fever, chills, or headache
Since many of these withdrawal symptoms mimic warning signs of other conditions and problems, an expert assessment by an addiction professional is necessary to determine whether marijuana withdrawal is the cause.
Treatment options or “rehab” for marijuana addiction is like treatment programs and protocols for addiction to alcohol and other drugs. Evidence-based therapies such as Twelve Step facilitation, cognitive-behavioral therapy, motivational enhancement therapy and other scientifically valid approaches can be effective addiction treatment options, depending on the individual’s situation, other drug abuse, and treatment needs. Crossroads has specific treatment plans for teenage drug and alcohol abuse.