If You Thought Marijuana was Harmless, Medical Researchers Have News for You
By Dragan M. Svrakic, MD, PhD, Patrick J. Lustman, PhD, Ashok Mallya, MD, Taylor Andrea Lynn, PhD, Rhonda Finney, RN, and Neda M Svrakic
In recent years, advocates for the decriminalization of marijuana have cited its purported therapeutic value for an array of illnesses including anxiety disorders, glaucoma, and nausea associated with chemotherapy. Increasing, however, medical evidence suggests that marijuana can be detrimental to both physical and mental health. We believe that efforts to decriminalize (remove legal sanctions to) or legalize (remove all prohibitions against) marijuana are misguided.
Regulation, Legislation, and History
Part of the problem is that both the medicinal use of smoked marijuana, and legalization or decriminalization of the cannabis plant itself, are being promoted in a way that bypasses the normal FDA approval process required for drugs marketed in the United States. This forces legislators and voters to decide on proposals that affect public health and medical treatment without necessarily understanding the relevant scientific evidence.
True, cannabis has been used historically in various cultures to treat sundry medical ailments. It was even recognized as an official drug in the U.S. in the 1800s. In 1970, however, the Controlled Substances Act classified it as illicit and made possession a felony because, like other drugs in its category, it has a high potential for abuse, has no currently accepted medical use in the U.S., and lacks adequate guidelines for safe use under medical supervision.
This hasn’t dampened the enthusiasm of significant parts of the population for using it, however. It’s long been considered relatively benign compared to opiates, stimulants, and even alcohol. Surveys reveal that 44% of men and 35% of women have used marijuana at least once, and regular use is on the rise.
Effects on General Health
It’s important to be informed, then, about the problems marijuana can cause. Concerns include the following:
Pulmonary: Smoking marijuana has documented adverse effects including decreased lung function, chronic cough, airway inflammation, and abnormal cell growth that may precede cancer onset. Many of the same mutagens and carcinogens found in tobacco smoke also occur in marijuana; in contrast to tobacco, however, marijuana-induced lung injury doesn’t go away after you quit.
Immunologic: HIV-positive cannabis users have been shown to have increased mortality versus those who don’t use cannabis.
Cardiovascular: Marijuana stimulates the heart’s natural pacemaker and is unsafe in cardiac patients.
Hepatic: Daily cannabis use can be harmful to patients with liver disease.
Endocrine and Reproductive: Research shows that cannabis compounds—cannabinoids—affect a variety of hormone levels and can disrupt female reproductive health. Women who smoke marijuana while pregnant are more likely to have low–birth-weight infants, and THC, the major psychoactive ingredient in marijuana, is passed along in breast milk.
Oncogenic: Studies show that cannabis use increases the incidence of testicular germ-cell tumors up to 70%, particularly in heavy or long-term users.
Among marijuana’s most troubling effects are those on mental health and cognitive function. Reported issues include mental slowness, tiredness, euphoria, anxiety, and paranoia. If euphoria doesn’t sound so bad, remember that what goes up must come down.
Researchers have shown that marijuana use decreases cortical dopamine, a chemical that plays a major role in cognition, memory, and executive functions. The feelings of relaxation, reduced anxiety, and peace reported by cannabis users are more likely cognitive dulling due to this dopamine decline. For that matter, active ingredients in cannabis, particularly THC, affect neurophysiological and behavior systems in ways similar to addictive drugs.
Cannabis users suffer mental health problems twice as often as nonusers. This raises an obvious chicken-or-egg question: do people smoke dope because they’re upset, or are they upset because they smoke dope? Increasingly, evidence supports the latter view. Long-term use is associated with anatomical abnormalities in the parts of the brain rich in cannabinoid receptors, and cannabis appears to significantly increase the risk of serious psychiatric illnesses such as schizophrenia and psychosis.
We believe that the future medical role for cannabinoid drugs lies with chemically modified extracts, not with unprocessed plants. Examples already exist, as in drugs approved to fight nausea and vomiting in chemotherapy patients, or those that show promise in wasting syndromes, neurologic disorders, and chronic pain. The public should be cautious about marijuana use in other contexts—particularly adolescents whose brains are still undergoing critical development or individuals predisposed to psychiatric illness. Anything else would be reefer madness.
Published March 19, 2012.