Harms of Recreational Marijuana

Analysis

Today’s highly potent marijuana—available in a variety of edible forms like chocolate, beverages, gummies, and cookies—exacerbate the negative outcomes associated with marijuana use. Marijuana, or cannabis, and its related products can be smoked, drunk, eaten, vaped or applied topically. The drug “acts by binding to cannabinoid receptors in the brain to produce a variety of effects, including euphoria, intoxication, and memory and motor impairments.”[i] Marijuana contains delta-9-tetrahydrocannabinol (THC), responsible for euphoria and intoxication, and cannabidiol (CBD), which is not intoxicating and not addictive, but “its long-term effects are largely unknown, and most CBD products are untested and of uncertain purity.”[ii]

The concentration of THC in marijuana plants and related products has increased drastically in recent years, from less than 4% in 1995 to 15% in 2021.[iii] Marijuana sold in dispensaries, in Washington state for example, have average THC concentrations from 17.7% and 23.2%,[iv] while concentrated products such as “oil, shatter, dab, and edibles” can have THC concentration levels up to 95%.[v] To put it in perspective, the marijuana of the 1960s to the 1980s had THC concentrations of less than 2%.[vi]

Legalization has led to a rise in the use of this high potency marijuana. A 2021 study showed a significant increase in use between 2011 and 2021, up 13.2%, while past-year, past-month, and daily use reached the highest levels ever recorded.[vii]

Harms to Health

Marijuana use is associated with significant health risks, especially with increased frequency of use and potency of the marijuana. 

Hospitalization. Legalization of recreational marijuana drastically increased the rate of hospitalizations related to marijuana use prior to the COVID pandemic. A 2019 study reviewed emergency department visits to UCHealth University Colorado Hospital from 2013 (when recreational marijuana was legalized in Colorado) to 2016 and found the number of marijuana-related emergency room visits more than tripled.[viii] The increase in health care facility visits nationwide continues, according to a 2022 National Library of Medicine report.[ix]  

The 2019 study showed edible marijuana products were more likely to send a person to the emergency room—usually with “[a]cute psychiatric visits like acute panic attacks, acute psychosis, and acute-on chronic conditions such as acute exacerbations of schizophrenia”—perhaps because people are ingesting unsafe levels and not feeling the effects until 2 or 3 hours after ingestion.[x] However, the data showed inhaled marijuana led to longer hospital visits, mostly caused by cannabinoid hyperemesis syndrome,[xi] characterized by abdominal pain, nausea, and frequent bouts of vomiting.

Effects on Brain Development. Human brain development begins before birth and continues into the mid-20s, making it “vulnerable to the effects of addictive substances,” like marijuana.[xii] The prefrontal motor cortex, known as the “seat of judgment,” may take 25 to even 30 years to fully develop.[xiii] As would be expected, frequent marijuana use while the brain is still developing is associated with “[c]hanges in the areas of the brain involved in attention, memory, decision-making, and motivation,”[xiv] and is associated with permanent IQ loss if frequent marijuana use begins in young adolescence and continues into adulthood.[xv] Therefore, even adult marijuana users—21 to 30 year olds—may be unknowingly harming their brains and thus jeopardizing their educational and professional achievements.                

Effects on Mental Health. Experts are acknowledging the link between marijuana use and psychosis, paranoia, and schizophrenia, especially with higher doses of THC.[xvi] In 2017, the National Academy of Medicine, a nonprofit group that advises the government on health and medical issues, released a landmark 468-page report, “The Health Effects of Cannabis and Cannabinoids.” After reviewing thirty years of research, a 16-member committee convened by the academy found that “cannabis use is likely to increase the risk of developing schizophrenia and other psychoses; the higher the use, the greater risk.”[xvii]

Similarly, in May 2019 a study compared over 900 patients with first-episode psychosis across locations in Europe and Brazil with over 1,200 people in the same locations who had not.[xviii] The study concluded “[d]aily cannabis use was associated with increased odds of psychotic disorder compared with never users . . ., increasing to nearly five-times increased odds for daily use of high-potency types of cannabis.”[xix]

In addition to psychosis, marijuana has been linked to anxiety, depression, and suicide. [xx] The latest data from Colorado bears this out: the number of suicides in Colorado where marijuana was present increased from 14% in 2013 to 29% in 2020. [xxi]

Vaping Lung Injuries and Deaths. Centers for Disease Control and Prevention (CDC), the U.S. Food and Drug Administration (FDA), state and local health departments, and other clinical and public health partner investigated a multistate outbreak of lung injury associated with use of e-cigarette, or vaping, products.[xxii] Although as of the CDC’s latest update in January, 2020, the CDC and FDA do not know the exact cause of the reported 2,668 injuries[xxiii] and at least 42 deaths, “CDC recommends that persons not use THC-containing e-cigarette, or vaping products, particularly from informal sources. Evidence is not sufficient to rule out the contribution of other chemicals of concern, including chemicals in either THC or non-THC-containing products, in some reported EVALI cases.”[xxiv]     

A March 2021 study showed adolescents who vaped THC suffered more severe lung damage than those who vaped or smoked nicotine.[xxv] Past month adult use of marijuana via vaping doubled between 2017 and 2021.[xxvi]

Harms to Society

DUI and Traffic Deaths. Studies have shown that marijuana “affects psychomotor skills and cognitive functions critical to driving including vigilance, drowsiness, time and distance perception, reaction time, divided attention, lane tracking, coordination, and balance.”[xxvii] As marijuana use increases with legalization, marijuana-related DUIs and traffic deaths will increase as well. For example, Colorado State Patrol DUI citations involving marijuana increased from 676 in 2014 to 1,041 in 2019.[xxviii] More tragically, since legalizing recreational marijuana in 2013, Colorado traffic deaths involving drivers who tested positive for marijuana more than doubled from 55 in 2013 to 131 in 2020, an increase of 138%, while overall traffic deaths increased 29%.[xxix]

Workforce Affected. Where recreational marijuana is legal, more employees go to work with marijuana in their system, putting those on the road and at work more at risk. For example, employees in Colorado and Washington State testing positive for marijuana rose almost 75% in the three years after legalization.[xxx] With more potential employees testing positive for marijuana, employers should find it more difficult to find employees, thereby negatively affecting the economy. However, because companies are having trouble finding people who can pass drug tests, many of them are simply choosing not to drug test anymore,[xxxi] thereby undermining the purpose of the drug tests in the first place.      

Crime and Violence. As shown above, studies have concluded “cannabis use is likely to increase the risk of developing schizophrenia and other psychoses; the higher the use, the greater risk.”[xxxii] Other studies have shown the link between psychotic disorders and violence.[xxxiii] For example, “Schizophrenia and Violence: Systematic Review and Analysis”—an article published in PLOS Medicine in 2009—examined twenty studies on people with schizophrenia and other forms of psychosis. [xxxiv] The study found that men with schizophrenia were four to five times more likely to commit a violent act than men without schizophrenia, and the risk was tenfold when the men were also substance abusers (including marijuana).[xxxv] In sum, legalizing recreational marijuana increases its use, thereby increasing the risk of schizophrenia, which inevitably will increase the risk of violent acts being committed.   

Harms to Children and Youth

U.S. Surgeon General Jerome Adams warns in his 2019 “Marijuana Use and the Developing Brain” advisory, “No amount of marijuana use during pregnancy or adolescence is known to be safe.”[xxxvi] And yet, legalizing recreational marijuana increases the use of marijuana among these populations.    

Increased Use Among Pregnant Women. Many dispensaries recommend marijuana to pregnant women to help with morning sickness,[xxxvii] even though health risks to them and their babies are very real. Citing a variety of studies, the U.S. Surgeon General warns that marijuana use during pregnancy can affect the developing baby: 1) THC can enter the baby’s brain from the mother’s bloodstream; 2) THC may disrupt the endocannabinoid system, which is important for a healthy pregnancy and for the baby’s brain development; and 3) Marijuana use is associated with low birth weight.[xxxviii]  The danger to the baby continues even after birth as THC has been found in breast milk days after the last recorded use of marijuana.[xxxix] In spite of these health risks, a 2017 study found that 70% out of 400 dispensaries contacted in Colorado recommended treating nausea in the first trimester with marijuana.[xl]   

A national survey recently found marijuana use among pregnant women doubled (3.4% to 7%) between 2002 and 2017, and a study done in a large health system in California found marijuana use among pregnant women rose 69% (4.2% to 7.1%) between 2009 and 2016.[xli] A 2022 National Library of Medicine study found a continued increase in marijuana use by pregnant women.[xlii] Legalizing recreational marijuana exacerbates this problem and puts even more pregnant women and their babies in harm’s way.  

The 2021 Arizona Legislature considered a bill that would have required labels warning of the dangers of inhaling or ingesting THC while pregnant, but it failed to get the required votes to pass.[xliii]

Increased Use Among Youth. Where recreational marijuana is legal, teens are more likely to use it. According to the data from the National Survey on Drug Use and Health (NSDUH) for 2016-2017, where recreational marijuana was legal at the time, 15.45% of minors aged 12 to 17 used marijuana in the prior year, with the highest rates in Vermont (17.9%), Colorado (17%), and Oregon (17%).[xliv] In contrast, the average for the illegal states was only 11.89%, with the lowest rates being Utah (9.2%), Texas (9.6%), and Alabama (9.7%).[xlv] These numbers make sense because 1) legalization itself “may be impacting youth perception of harm from marijuana,”[xlvi] making them think it is safer than it actually is and  2) legalization makes marijuana more accessible to youth— critical because they usually get their marijuana free from friends and relatives.[xlvii]

The NSDUH report for 2018-2019 shows a statistically significant increase in marijuana use by youths 12 and older, with past year use jumping from 15.9% to 17.5%.[xlviii]

The health risks of marijuana, as outlined above, affect the young even worse. As the U.S. Surgeon General has warned, the developing brain of a teenager is more vulnerable to the addictive effects of marijuana, and frequent marijuana use during teenage years is associated with impairment of attention, memory, decision-making, and motivation, as well as loss of IQ, increased rates of school absence and drop-out rates, suicide attempts, early onset of psychotic disorders, and greater likelihood of misusing opioids.[xlix]     

Accidental Ingestion by Children and Youth. Where recreational marijuana is legalized, the rate of accidental ingestion by children and youth increases. Edibles with concentrated doses of THC in the form of candy, snacks, and beverages are often indistinguishable for small children and attractive for teens. Also, because edibles take time to absorb and to produce its effects, the potential for overdose is much greater when “an entire product containing multiple dose-units”[l] is consumed.

A study analyzed “single substance, human exposure calls coded to marijuana brownies, candies, cookies, beverages, or other foods” reported to the National Poison Data system from January 2013 to December 2015; it found the highest number of calls came from Colorado and Washington, with 91% of all calls occurring from states with decriminalized medical or recreational marijuana.[li] This study matches the data coming out of Colorado, where the Rocky Mountain Poison and Drug Center reported marijuana-related exposures in children and teens increasing from 50 in 2012 (year before recreational marijuana was legalized) to 147 in 2018.[lii]      

A March 2021 study found children under 10-years-old were most likely to be the victims of apparent accidental ingestion of edibles, concentrates, and liquids, and that such cases happen most frequently in states that legalized recreational marijuana.[liii]

Although downplayed by some, “[u]nintentional cannabis ingestion by children is a serious public health concern and is well-documented in numerous studies and case reports.”[liv] 

Talking Points

• Today’s marijuana is 10 to 50 times more potent than it was in the 1970s, depending on the form. This newer, high potency marijuana is linked to schizophrenia and other psychoses, as well as several other significant health risks.
• Where recreational marijuana is legal, more people use it, more people drive under the influence, work under the influence, and end up in the hospital. And regardless of age restrictions, more teens use it where it is legal, and more children are hospitalized after accidentally eating marijuana-laced candy and snacks.
• Legalizing recreational marijuana puts families at risk, because where recreational marijuana is legal, more people drive stoned, and more people die in marijuana-related traffic crashes.
• Self-serving marijuana insiders downplay the risks of marijuana, much like the tobacco industry ignored the lung cancer risks of cigarettes years ago.