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    Marijuana for Dummies: Separating the Fact and Fiction of Cannabis - July 2006

    Whether you call it weed, herb, ganja or pot, the fact remains that marijuana use among adolescents is a major health issue today. Despite the fact that more than half of the U.S. population has tried marijuana at some point in their lives(1), few know its actual health risks and benefits. Instead, both parents and youth can get lost in the haze of myth and misinformation.

    Unfortunately, the internet, a place where many of us turn for information on a wide range of topics, is loaded with misleading information. Some sites even refer to journal articles that supposedly “prove” that marijuana is not harmful. The truth is that marijuana can be quite harmful, especially when it is smoked. How do we sort fact from fiction? Let’s break down some basic Marijuana Myths.

    Myth #1: Smoking weed is less harmful than smoking cigarettes.
    As plant products, marijuana and tobacco share over 400 identical compounds, many of which promote cancer when burned. During a typical draw on a joint, individuals usually inhale deeper, expanding their lungs to a volume that is roughly two-thirds larger than with cigarette smoking. In addition, the average marijuana smoker holds the breath for four times as long as a cigarette smoker. Smoking in this manner (combined with the lack of a filter on a joint) leads marijuana users to receive four times the amount of tar and five times the amount of carbon monoxide per cigarette than users of tobacco(2). Like tobacco, smoking marijuana has been shown to cause severe irritation and physical changes to the cells that line the airways of the lung(3). Three to four joints have been shown to produce the same amount of damage as 22 tobacco cigarettes(4). In addition, smoking cannabis has been associated with emphysema(5,6) and increased risk of cancer of the head and neck (particularly the tongue and throat).(7)

    Myth #2: Marijuana is not addictive.
    The generally held notion that marijuana cannot be addictive turns out to be false. Similar to alcohol, it has been shown that, although most individuals who use marijuana do not become dependent, many do. Marijuana acts on the same addiction centers of the brain as nicotine, cocaine and heroin(8). The difference has to do with how quickly it is cleared from the body. Unlike other drugs, marijuana is stored by fat cells and stays in the body for long periods of time. This is the reason why drug tests for marijuana can be positive for weeks to months after the drug was last used. Because of the gradual decline in marijuana levels in the blood, many users do not notice withdrawal symptoms. However, marijuana withdrawal definitely exists. Symptoms include nausea, shakiness, sweating, poor sleep, restlessness, agitation, irritability and depressed mood(9).

    Myth #3: Smoking through a bong or a water pipe is “safer” because the water filters the smoke.
    In truth, the water in a ‘bong’ has been shown to cool the smoke and deliver a more concentrated effect to the lungs(10).

    Myth #4: Driving under the influence of marijuana is not dangerous because it helps you to be a more “mellow driver”.
    In the USA, UK, Australia, New Zealand and many European countries marijuana is the most common drug apart from alcohol to be detected in drivers who are involved in fatal accidents or stopped for impaired driving(11). Alone, marijuana has effects similar to those of alcohol or Valium. It causes slowed reaction time as well as inhibition of motor coordination, short-term memory, concentration and completion of complex tasks that require divided attention(12). The effects of marijuana and alcohol together are additive and produce an increased degree of impairment, though studies show that marijuana alone is associated with increased traffic accidents.

    Myth #5: Smoking marijuana during pregnancy is not harmful to the fetus.
    Just as smoking tobacco during pregnancy has been shown to be harm to the fetus, smoking marijuana has also been reported to cause intrauterine growth restriction and low birth-weight babies(13). Studies have also shown that paternal marijuana use during conception, pregnancy and after birth was associated with increased occurrence of Sudden Infant Death Syndrome (SIDS)(14).

    Most of the worst health effects associated with marijuana use result from smoking. However, even when it is not smoked, the herb can have harmful effects on the body and mind. Cannabis has been found to lower testosterone levels in males and is associated with decreased sex drive, impotence, reduced testicular size and the development of breasts in boys and men (gynecomastia). In women it has been linked to menstrual abnormalities, abnormal ova and prolonged childbirth. In addition, though it is known to cause relaxation in the average person, for anyone who struggles with mental illness, such as anxiety, depression or schizophrenia, it can make those disorders worse.

    Far from harmless, marijuana is known to cause numerous health problems in youth as well as adults. However, because it is so common, many youth today know someone who smokes weed on a regular basis and seems to be “fine” or even “more creative” when they are under the influence. It is important for both parents and kids to be aware of the actual health risks associated with marijuana. Similarly to alcohol and tobacco, this socially ubiquitous drug also carries major health hazards.

    References:

    1. Von Sydow, K et al “The natural course of cannabis use, abuse and dependence over four years: a longitudinal community study of adolescents and young adults.” Drug and Alcohol Dependence 2001 Nov;64(3):347-61

    2. Wu, T.C. “Pulmonary Hazards Of Smoking Marijuana As Compared To Tobacco.” New England Journal of Medicine 1998 Feb; 318(6):347-51

    3. Fliegiel et al “Tracheobronchial Histpathology in Habitual Smokers of Cocaine, Marijuana, and/or Tobacco.” Chest 1997 Aug; 112(2): 319-326

    4. Ibid

    5. Benson, M.K., Bentley, A.M. “Lung disease Induced By Drug Addiction.”
      Thorax 1995 Nov; 50(11): 1125-1127

    6. Johnson et al “Large Lung Bullae In Marijuana Smokers.” Thorax 2000 April; 55(4): 340-342

    7. Carriot, F., Sasco,A.J. “Cannabis et Cancer” Revue D’Epidemiologie et de Sante Publique 2000 Oct; 48(5)473-483 *Citation taken from English language abstract of French Publication.

    8. Hubbard, J.R. “Marijuana: Medical Implications” American Family Physician 1999 Dec; 60(9):

    9. Ibid

    10. Ibid

    11. Ibid

    12. NHTSA Notes “Maraijuana and Alcohol Combined Severely Impede Driving Performance.” Annals of Emergency Medicine 2000 April; 35(4):

    13. Ibid

    14. Knonoff-Cohen, H. and Lam-Kruglick, P. “Maternal and Paternal Recreational Drug Use and Sudden Infant Death Syndrome.” Archives of Pediatrics and Adolescent Medicine 2001 July; 155(7):765-770

    This information provided by Nadine Burke, M.D., Medical Director, Pediatric Health Parity Programs, California Pacific Medical Center's Department of Pediatrics.