Health Effects of Marijuana
Usually smoked as a cigarette or joint, or in a pipe or bong, marijuana has appeared in "blunts" in recent years. These are cigars that have been emptied of tobacco and re-filled with marijuana, sometimes in combination with another drug, such as crack. Some users also mix marijuana into foods or use it to brew tea.
The main active chemical in marijuana is THC (delta-9-tetrahydrocannabinol). Short-term effects of marijuana use include problems with memory and learning; distorted perception; difficulty in thinking and problem-solving; loss of coordination; and increased heart rate, anxiety, and panic attacks.
Effects of Marijuana on the Brain. Researchers have found that THC changes the way in which sensory information gets into and is acted on by the hippocampus. This is a component of the brain's limbic system that is crucial for learning, memory, and the integration of sensory experiences with emotions and motivations. Investigations have shown that THC suppresses neurons in the information-processing system of the hippocampus. In addition, researchers have discovered that learned behaviors, which depend on the hippocampus, also deteriorate. Take the virtual tour to learn more about the effects of marijuana on the brain.
Effects on the Lungs. Someone who smokes marijuana regularly may have many of the same respiratory problems that tobacco smokers have. These individuals may have daily cough and phlegm, symptoms of chronic bronchitis, and more frequent chest colds. Continuing to smoke marijuana can lead to abnormal functioning of lung tissue injured or destroyed by marijuana smoke.
Regardless of the THC content, the amount of tar inhaled by marijuana smokers and the level of carbon monoxide absorbed are three to five times greater than among tobacco smokers. This may be due to marijuana users inhaling more deeply and holding the smoke in the lungs.
Effects of Heavy Marijuana Use on Learning and Social Behavior. A study of college students has shown that critical skills related to attention, memory, and learning are impaired among people who use marijuana heavily, even after discontinuing its use for at least 24 hours. Researchers compared 65 "heavy users," who had smoked marijuana a median of 29 of the past 30 days, and 64 "light users," who had smoked a median of 1 of the past 30 days. After a closely monitored 19- to 24-hour period of abstinence from marijuana and other illegal drugs and alcohol, the undergraduates were given several standard tests measuring aspects of attention, memory, and learning. Compared to the light users, heavy marijuana users made more errors and had more difficulty sustaining attention, shifting attention to meet the demands of changes in the environment, and in registering, processing, and using information. The findings suggest that the greater impairment among heavy users is likely due to an alteration of brain activity produced by marijuana.
Longitudinal research on marijuana use among young people below college age indicates those who used have lower achievement than the non-users, more acceptance of deviant behavior, more delinquent behavior and aggression, greater rebelliousness, poorer relationships with parents, and more associations with delinquent and drug-using friends.
Information provided by the National Institute on Drug Abuse.
What's the Big Deal About Marijuana?
"But it's only marijuana" or "it's only alcohol," you say. "It's a rite of passage." "Teens are expected to experiment." Not any more. The world has changed, and so have the drugs. In fact, the marijuana of today is stronger than ever before. Drug and alcohol use can lead to many negative consequences, including bad grades, broken friendships, family problems, trouble with the law, etc.
Most important, teens' brains and bodies are still developing, and substance use can interfere with their emerging independence and efforts to establish their own identity. Drug and alcohol use can change the direction of a young person's life – physically, emotionally, and behaviorally. It can weaken the ability to concentrate and retain information during a teen's peak learning years, and impair judgment leading to risky decision making that could involve sex or getting into a car with someone under the influence of drugs.
"Experimentation," even with marijuana, can also lead to addiction. Not everyone progresses from use to abuse to addiction, but it is a dangerous road and there is no way to know who will become addicted and who won't.
Scientific Research About Risks of "Experimentation"
Drug and alcohol abuse by teens is not something to be taken lightly.
- More teens are in treatment with a primary diagnosis of marijuana dependence than for all other illegal drugs combined.
- Research also shows that many adolescents start to drink at very young ages. In 2003, the average age of first use of alcohol was about 14, compared to about 17 1/2 in 1965.
- A 1998 study by the National Institute on Alcohol Abuse and Alcoholism says if a 15-year-old starts to drink, he or she has a 40% chance of alcoholism or dependence as an adult.
- Kids are using marijuana at an earlier age. In the late 1960s fewer than half of those using marijuana for the first time were under 18. In 2006, about 64 percent of marijuana users were younger than 18.
- Marijuana affects alertness, concentration, perception, coordination and reaction time, many of the skills required for safe driving and other tasks. These effects can last up to 24 hours after smoking marijuana. Marijuana use can also make it difficult to judge distances and react to signals and sounds on the road.
- Smoking marijuana leads to changes in the brain that are similar to those caused by cocaine, heroin, or alcohol.
Parents Are the Most Important Influence in a Child's Life
There is a growing body of research that shows that parents are central to preventing adolescent substance abuse. In fact, kids themselves say that losing their parents' trust and respect are the most important reasons not to use drugs.
As a parent, your actions do matter. When you suspect, or know, that your child has used drugs, take action to stop it as soon as you can. It may be the most important step you ever take.
- TEDS, SAMHSA, October 2001
- Newes-Adeyi, G.; Chen, C.M.; Williams, G.D.; and Faden, V.B. NIAAA Surveillance Report No. 74: Trends in Underage Drinking in the United States, 1991–2003. Bethesda, MD: National Institute on Alcohol Abuse and Alcoholism, 2005.
- Grant, B.F., and Dawson, D.A. Age of onset of alcohol use and its association with DSM–IV alcohol abuse and dependence: Results from the National Longitudinal Alcohol Epidemiologic Survey. Journal of Substance Abuse 9:103–110, 1997.
- Trends in Initiation of Substance Use. Based on the 2005 National Survey on Drug Use and Health. SAMHSA, 2006.
- Marijuana: Facts Parents Need to Know, Revised, NIDA, November 1998
- Marijuana: Facts Parents Need to Know, Revised, NIDA, November 1998
Do you know the facts about marijuana? Here are some common myths.
MYTH: Marijuana is harmless.
FACT: Marijuana is the most widely used illegal drug among youth today and is more potent than ever. Marijuana use can lead to a host of significant health, social, learning, and behavioral problems at a crucial time in a young person's development. Getting high also impairs judgment, which can lead to risky decision making on issues like sex, criminal activity, or riding with someone who is under the influence of drugs or alcohol. According to the National Center on Addiction and Substance Abuse (CASA) at Columbia University, teens who use drugs are five times more likely to have sex than teens who do not use drugs. Getting high also contributes to general apathy, irresponsible behavior, and risky choices.
MYTH: You can't get addicted to marijuana.
FACT: Don’t be fooled by popular beliefs. Kids can get hooked on pot. Research shows that marijuana use can lead to addiction. Each year, more kids enter treatment with a primary diagnosis of marijuana dependence than for all other illegal drugs combined.
MYTH: There's not much parents can do to stop their kids from "experimenting" with marijuana.
FACT: Most parents are surprised to learn that they are the most powerful influence on their children when it comes to drugs. But, it's true, so this message needs to start with parents. Kids need to hear how risky marijuana use can be. They need to know how damaging it can be to their lives. And they need to begin by listening to someone they trust. By staying involved, knowing what their kids are doing, and setting limits with clear rules and consequences, parents can keep their kids drug-free.
MYTH: There are no long-term consequences to marijuana use.
FACT: Research shows that kids who smoke marijuana engage in risky behavior that can jeopardize their futures, like having sex, getting in trouble with the law, or losing scholarship money. Marijuana can also hurt academic achievement and puts kids at risk for depression and anxiety.
MYTH: Marijuana isn't as popular as other drugs like ecstasy among teens today.
FACT: Kids use marijuana far more than any other illegal drug. Among kids who use drugs, 60 percent use only marijuana.
MYTH: Young kids won't be exposed to marijuana.
FACT: While overall marijuana use has decreased, many children and teens are still using it. According to the annual Monitoring the Future national poll, in the past seven years, the number of eighth graders who had used marijuana decreased from approximately one in five to slightly more than one in 10. With recent research now linking marijuana use to mental health disorders like depression and schizophrenia, this is still far too many. The same report notes that, by 12th grade, marijuana use increases to more than two in five teens.
MYTH: Parents who experimented with marijuana in their youth would be hypocrites if they told their kids not to try it.
FACT: Parents need to make their own decisions about whether to talk to their children about their own drug use. But parents can tell their kids that much more is known today about the serious health and social consequences of using marijuana.
Information taken from www.theantidrug.com
HOW MARIJUANA EFFECTS LEARNING:
As your teens go through high school and prepare for college they are at an increased risk for drug use and drinking. However, high school is the critical point in building the academic foundation for the rest of their lives. Be sure your teens remain drug-free during these critical learning years.
Marijuana is riskier than you think. It can limit your teen’s achievement in the classroom, on standardized tests and in the future.
- Marijuana can hinder a teen's ability to learn. Heavy marijuana use impairs young people's ability to concentrate and retain information.This can be especially problematic during peak learning years.
- Marijuana use is linked to poorer grades. A teen with a "D" average is four times more likely to have used marijuana than a teen with an "A" average.
- Marijuana and underage drinking are linked to higher dropout rates. Students who drink or use drugs frequently are up to five times more likely than their peers to drop out of high school. A teenage marijuana user's odds of dropping out are more than twice that of a non-user.
Marijuana is addictive. It can cause problems for young users when their bodies and brains are still developing, which decreases their likelihood of success.
- Research also shows that marijuana use is three times more likely to lead to dependence among adolescents than among adults. Research indicates that the earlier kids start using marijuana, the more likely they are to become dependent on this or other illicit drugs later in life.
- Teens who begin marijuana use at an early age when the brain is still developing may be more vulnerable to neuropsychological deficits, especially verbal abilities.
- Teens who are regular marijuana users often have short attention spans, decreased energy and ambition, poor judgment, impaired communications skills and diminished effectiveness in social situations — a set of problems called an "amotivational syndrome" by scientists.
Parents need to know the facts about marijuana. Setting rules and enforcing them can make all the difference in teens' lives.
- Youths who are not regularly monitored by their parents are four times more likely to use drugs.
- Parents are the most powerful influence on their kids when it comes to drugs. Two-thirds of youth ages 13-17 say losing their parents' respect is one of the main reasons they don't smoke marijuana or use other drugs.
- Parental disapproval plays a strong role in turning back drug use. In 2004, youths who believed that their parents would strongly disapprove of marijuana use had rates over 80 percent lower than those whose parents would not strongly disapprove (5.1 percent use vs. 30 percent use rates).
- Kids who learn about the risks of marijuana and other illicit drugs from their parents are far less likely to use drugs.
- Pope HG et al. Early-onset cannabis use and cognitive deficits: What is the nature of the association? Drug and Alcohol Dependence.,69 (3): 303-310, 2003.
- The National Household Survey on Drug Abuse (NHSDA) Report: Marijuana use among youths. SAMHSA, 2002. Based on data from the National Household Survey on Drug Abuse 2000.
- The National Center on Addiction and Substance Abuse at Columbia University (CASA). Malignant neglect: Substance abuse and America’s schools. New York: Columbia University, 2001.
- Bray JW et al. The relationship between marijuana initiation and dropping out of school. Health Economics.,9(1): 9-18, 2000.
- Youth Marijuana Prevention Initiative:The NCADI Report. U.S. Department of Health and Human Services, October 2002. Gfroerer, JC and Epstein, JF. Marijuana initiates and their impact on future drug abuse treatment need. Drug and Alcohol Dependence.,54(3):229-237, 1999. Anthony, JC and Petronis, KR. Early-onset drug use and risk of later drug problems. Drug and Alcohol Dependence., 40: 9-15, 1995. Grant, BF and Dawson, DA. Age of onset of drug use and its association with DSM-IV drug abuse and dependence: Results from the National Longitudinal Alcohol Epidemiologic Survey. Journal of Substance Abuse,10: 163-173, 1998.
- Pope, HG et al. Early-onset cannabis use and cognitive deficits: what is the nature of the association? Drug and Alcohol Dependence.,69 (3): 303-310, 2003.
- Metzler, Rusby and Biglan. Community builders for success: monitoring after-school activities. Oregon Research Institute, 1999.
- Partnership for a Drug-Free America Attitude Tracking Study, 2002.
- National Survey on Drug Use and Health 2004. SAMHSA, 2005.
- Greenblat, J. Self-reported behaviors and their association with marijuana use. SAMHSA. Based on data from the National Household Survey on Drug Abuse, 1994-1996.
Marijuana and Mental Health
Marijuana and Depression.
Marijuana and Suicidal Thoughts.
Marijuana and Schizophrenia.
Do we have your attention? As parents and caregivers, you probably never thought you’d see marijuana associated with these mental health problems … but it is. New research is giving us better insight into the serious consequences of teen marijuana use, especially how it impacts mental health.
Today’s teens are smoking a more potent form of marijuana and starting use at increasingly younger ages during crucial brain development years. There is plenty of evidence indicating the ways pot impedes, even changes, the mental health of adolescents. In fact, those changes in the brain are similar to those caused by cocaine, heroin and alcohol. The overall impact that pot has on the brain can have long term consequences, and it’s up to you to influence your teen’s life when it comes to drugs.
Weekly or more frequent use of marijuana can double a teen’s risk of depression and anxiety.Teens who smoke marijuana when feeling depressed are also more likely to become addicted to marijuana or other illicit drugs. Eight percent of depressed teens abused or became dependent on marijuana during the year they experienced depression compared with only three percent of non-depressed teens.
Teen girls are especially at risk. More girls than boys felt depressed in the course of a year and substance abuse can compound the problem. Daily use of marijuana among girls is associated with a fivefold increase in the odds of developing depression and anxiety.
Marijuana can also be linked to suicidal thoughts. A study based on data from the National Household Survey on Drug Abuse found that teenagers 12 to 17 who smoke marijuana weekly are three times more likely to have thoughts of committing suicide. The same study linked increased anxiety and panic attacks to past year marijuana use.
Several studies have documented marijuana’s link with symptoms of schizophrenia and report that cannabis is an independent risk factor for schizophrenia. Heavy users of marijuana at age 18 increased their risk of schizophrenia later in life by six times.
Further reports have found marijuana use increased the risk of developing schizophrenia among people with no prior history of a disorder, and that early use of marijuana (age 15 vs. age 18) increased the risk even more. In addition, youth with a personal or family history of schizophrenia are at an even greater risk of marijuana-induced psychosis.
Let your teens know you don’t want them using marijuana. Their mental health may depend on it.
- El Sohly, M.A. University of Mississippi Potency Monitoring Project, 2004
- Marijuana: Facts Parents Need to Know, Revised, NIDA, November 1998
- Patton, GC et al. Cannabis use and mental health in young people: cohort study. British Medical Journal, 325:1195-1198, 2002.
- 2006 National Survey on Drug Use and Health, SAMHSA, 2007. Table 6.36B. http://www.oas.samhsa.gov/NSDUH/2k6nsduh/tabs/Sect6peTabs36to37.pdf
- Patton, G.Cet al. Cannabis use and mental health in young people: cohort study. BMJ 325, 1195-1198, 2002.
- Greenblatt, J. (1998), Adolescent self-reported behaviors and their association with marijuana use. National Household Survey on Drug Abuse, 1994-1996 SAMHSA
- Andreasson, S. et al. Cannabis and schizophrenia: A longitudinal study of Swedish conscripts. Lancet, 26: 1483-1486, 1987
- Arseneault L., et al. Causal association between cannabis and psychosis: examination of the evidence. British Journal of Psychiatry, 184: 110-117, 2004