"Marijuana is no big problem – everyone uses it"

Cannabis is the most common substance of dependence in youth.

The number of youth (22%) and young adults (26%) who used marijuana in 2013 was more than two and a half times that of adults 25 and older (8%).  Statistics Canada’s Canadian Tobacco, Alcohol and Drug Survey (CTADS)2013. 

In general, substance use has moved into the mainstream adolescent population and to younger age groups. Cannabis is the most common substance of daily use by adolescents, more than alcohol.  (5-6% of senior high school students vs. alcohol at 2.5-3%).  Milin 2014

This CTV News report takes a look at some of the issues surrounding teen use of  marijuana.

Part Two of the CTVNews report  - A substance abuse counsellor who advises kids in school talks about the risks and how parents should talk to their kids. 



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.
Marijuana Pipe

Health Hazards

The Effects of Marijuana on the Brain.

How cannibis works on 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 behaviours, which depend on the hippocampus, also deteriorate. (Illustration from Demystifying Marijuana Dependence, Dr Milin 2014)

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 Behaviour-

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 behaviour, more delinquent behaviour and aggression, greater rebelliousness, poorer relationships with parents, and more associations with delinquent and drug-using friends.

Negative Effects of Marijuana

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 behaviourally. 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.

Substance Use Disorder and Teenagers

From a developmental perspective, adolescence may be a unique period of heightened susceptibility for Substance Use Disorders– or SUD.  The convergence of major psychosocial challenges (stresses) and maturational neuro-developmental brain changes in adolescence may enhance their vulnerability to the effects of substance use.

Adolescence is a period of major risk for the onset of SUD.   In general, peak age of Substance Use Disorder onset is between ages 18-20.   However, the peak age of onset for Cannabis Use Disorder  or CUD is younger, 16-18 years old.   Demystifying Marijuana Dependence, Dr Milin 2014


Cannabis Use Disorder ( CUD)  and how it affects adolescents

  • Acute panic reactions or mild paranoia have been observed.
  •  May also lead to an acute toxic psychosis accompanied by loss of insight.
  • Heavy and frequent marijuana use (daily use in past 30 days) is associated with significantly greater impairment than light use (1-9 days of use in past 30 days) on attentional and executive functions.
  • Short-term/working memory impairment may persist for some time on neuropsychological testing (up to 3 months).
  • Solid evidence that persistent regular cannabis use (4 day/week) and/or dependence in adolescence is associated with broad based neuropsychological decline in adulthood.
  • Greater the duration of use the greater the decline
  • Negative impact on functioning
  • Cessation of cannabis did not fully restore neuropsychological profile, even after controlling for years of education
  • Meier et al, 2012 in Demystifying Marijuana Dependence, Dr Milin 2014

"Marijuana helps me cope"

  • Depressed adolescents are 2X more likely to abuse or become dependent on marijuana
  • Frequent cannabis use in adolescence increases the risk for depression and anxiety, especially in young women.
  • Substance use (1° marijuana) has a negative impact on treatment response in adolescent MDD
  • Increased risk of psychosis:
  •  40% for ever used cannabis
  •  50-200% for used cannabis most frequently
  • Preliminary findings suggest a link between higher potency cannabis and development of first episode psychosis
  • Evidence, however, to date doesn’t support a causal link between cannabis use and schizophrenia
  • Nonetheless there is now sufficient evidence to warn young people that cannabis use may increase their risk for developing a psychotic disorder in adulthood
  • Converging epidemiological and clinical evidence to show:
  • CIPD not a random event or benign condition.
  • Drug induced psychotic disorder represents a cogent vulnerability marker for development of schizophrenia
  • Clinical follow-up of CIPD is warranted.


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.1
  • 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 1965.2
  • 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.3
  • 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 18.4
  • 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.5
  • Smoking marijuana leads to changes in the brain that are similar to those caused by cocaine, heroin, or alcohol.6
  • Early initiation of substance use, at 15 years or younger has been shown to increase the risk for:
    • Continued use and subsequent daily use.
    • Other Substance Use Disorders in adulthood apart from cannabis.
    • Weekly cannabis use marks a threshold for increased risk of later dependence.  
    • from Demystifying Marijuana Dependence, Dr Milin 2014


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.

That said, many teens will experiment with drugs for any number of reasons, it’s not a reflection on you, or your parenting. You can take steps to make sure that your child gets through it safely, by staying informed about drugs and by talking to your teen, even if it’s difficult. Keeping the lines of communication open can make a big difference in preventing drug use.

If you suspect or know that your teen is abusing drugs regularly, take action to get the help your teen needs and deserves. It may be the most important step you ever take.

1. 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.
2. 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.
3. 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.
4. Bray JW et al. The relationship between marijuana initiation and dropping out of school. Health Economics.,9(1): 9-18, 2000.
5. 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.
6. 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.