Medically Reviewed by
Jason Crawford

Article Last Updated on January 11, 2023

The marijuana industry is booming and both cannabis users and cannabis growers are looking forward to the changing marijuana policies and the legalization of marijuana. 

However, the marijuana laws passed by the federal government are very different from state laws. In fact, neither recreational marijuana nor medical marijuana is legal on a federal level in the US, which is why a lot of Americans are still getting arrested each year for illegal marijuana possession.

This is why proponents of legalizing marijuana, who believe that these laws will help create new jobs, improve the economy, lower street crime and drug cartels prevalence, as well as enable patients with medical issues to be eligible for medical marijuana treatment all over the US, fight for marijuana legalization and grow in number by the day.

Opponents of legalizing marijuana, on the other hand, believe that its negative effects outweigh the positive ones, by marijuana often being a gateway drug for more serious drug use, and that legalization of weed will lead to more addiction, crime, traffic deaths as a result of intoxication, and even workplace accidents. This is also a side of the cannabis story that we have yet to cover in an article, so this one will focus on the reasons why weed should not be legalized.

Current Marijuana Laws in the US

The policy on cannabis use in the US has undergone a lot of change in the past 50 years, from marijuana being illegal in all states and classified as a Schedule I drug with a high potential for dependency and no medical use with the passing of the Controlled Substances Act (CSA) back in 1971, to it slowly being legalized in US states in the last 20 years. Currently, medical marijuana is legal in 36 US states and the District of Columbia, while recreational marijuana is legal in 18 states and the District of Columbia.

CBD, on the other hand, has been legalized on a federal level with the passing of the 2018 Farm Bill. The only restriction when it comes to the legality of CBD is that all CBD products must be sourced from the industrial cannabis plant and contain no more than 0.3% THC to be eligible for cultivation and purchase.

Since the reasons why weed should not be legalized are the main focus of this article, let’s get into more detail in the following paragraphs.

Reasons Why Marijuana Should Not Be Legalised

Legalizing recreational and medical marijuana is a broad subject since it has implications on the domestic criminal justice policy as well as international drug cartels, public health, and also state and federal tax revenue. Contrary to the proponents of marijuana legalization, opponents also have their reasons why weed should not be legalized, so let’s see what they are.

Legalizing Marijuana Can Lead To More Marijuana-Related Medical Emergencies

According to an annual report in the Rocky Mountain High Intensity Drug Trafficking Area on the “Legalization of Marijuana in Colorado,” there was an increase in emergency room visits related to marijuana consumption after weed was legalized in the state. Ever since marijuana became legal in Colorado, there have been substantial changes, such as:

  • Traffic deaths increased by 31% and traffic deaths where drivers tested positive for weed increased by 109%.
  • Marijuana use for youths aged 12 and older increased by 58%.
  • Adult marijuana use increased by 94%.
  • Marijuana users in college students increased by 18%.
  • Youth marijuana use increased by 14%.
  • The yearly number of ER visits related to marijuana use increased by 54%.
  • Marijuana-related hospitalizations increased by 101%.
  • Suicide incidents in which the people were positive for marijuana increased to 23% in 2017 from 14% in 2013.

Marijuana Use Affects Brain Health and Increases Mental Health Problems

In a survey on the adverse effects of cannabis use, marijuana users reported that weed had effects on their mental health. In fact, 22% of users reported anxiety and panic attacks, while 15% reported psychotic symptoms.

A 2020 review on cannabis and mental illness by the Centre for Addiction and Mental Health (CAMH) and the Department of Psychiatry at the University of Toronto, reviewed popular research on cannabis use and its relation to the development of schizophrenia, depression, paranoia, and other psychiatric disorders. 

Furthermore, research done by Northwestern University concluded that recreational marijuana use among students was linked to decreased brain health and the development of brain abnormalities.

All in all, marijuana use, especially consuming large doses of cannabis for a long period of time, can highly impact your brain health. Long-term cannabis users have the risk of developing anxiety and panic attacks, while for those who have the predisposition for developing schizophrenia, depression, or paranoia, long-term cannabis use can become a trigger for the development of these conditions.

Marijuana Use Affects Your Health and the Health of the People Around You

Research shows that smoking marijuana long-term causes respiratory problems and damages the lung tissues. The concentration of carbon monoxide and tar in marijuana is significantly higher than the one in tobacco, which means that smoking weed may be even more harmful than smoking tobacco in some cases. Smoking cannabis can also result in neurobehavioral impairment which means that cannabis users should refrain from driving or operating heavy machinery until the effects of weed wear off. Finally, secondhand smoke is harmful to people who are staying in the same room as cannabis smokers, which is why regular ventilation is essential to prevent unwanted side effects.

Legalizing Marijuana May Result in Increased Teen Use

Substance abuse is becoming more and more prevalent among young people, especially in states where recreational marijuana is legalized. Teen cannabis use may increase as more states legalize weed, which means a higher national percentage of teen cannabis users. This is another reason for not legalizing marijuana since cannabis is harmful to young adults as it has detrimental effects on the adolescent brain. 

According to a 2014 review on the neuroimaging, neurocognitive, and preclinical findings on the effects of cannabis on the adolescent brain, teenagers who use marijuana in large doses show a lower neurocognitive performance and have problems with the macrostructural and microstructural brain development. As stated in a policy statement by the American Academy of Pediatrics, marijuana use in youths may result in short-term memory impairment, lower attention span and concentration, and difficulty with problem-solving, which is a serious problem that may interfere with learning.

“Big Marijuana” May Become the New “Big Tobacco”

Similar to how the big tobacco market expanded all over the world, the same can be expected after new marijuana legalization laws and drug policies are passed. What is problematic here is that children and young adults will also be affected by the expansion of this market as marijuana products already come in the form of popular kid-friendly snacks and treats, such as gummy bears, lollipops, and brownies.

Legalizing Marijuana May Decrease Productivity in the Workplace

As a result of the legalization of weed, workplace incidents with employees under the influence of weed have increased from 6% to 20% according to research. Employees using cannabis had 55% more industrial accidents and 85% more injuries, which also holds the employers liable in the case of workplace accidents. Furthermore, regular cannabis use impacts parts of the brain responsible for motivation which means that cannabis users could be less motivated in the workplace.

Growing Marijuana and Its Effects on the Environment

Another reason why people oppose marijuana legalization is the devastating effects that cannabis cultivation has on the environment, such as soil erosion, deforestation, river diversion, and habitat destruction. Growing weed requires double the amount of water that you’d need to grow tomatoes or similar crops. On the other hand, indoor cultivation requires the use of a lot of electricity for ventilation, heating, and lighting, which also increases the amount of greenhouse gas emissions.

Legalizing Marijuana and the Opinion of Major Public Health Organizations

A number of public health associations oppose legalizing marijuana because of the adverse effects it may cause in users. Those include:

  • American Medical Association (AMA);
  • American Society of Addiction Medicine (ASAM);
  • American Academy of Child and Adolescent Psychiatry;
  • American Academy of Pediatrics.

Most of these associations suggest that the legalization of cannabis should be postponed until more research is done on the effects of cannabis on users.

The Cost of Legalized Marijuana Outweighs Its Tax Revenues

The cost of legalizing marijuana can be viewed through a few factors, such as increased medical care and emergency room visits for patients who consumed larger doses of weed, addiction treatment for users who have developed cannabis use disorder, increased number of victims as a result of drugged driving accidents, as well as a negative impact on public health from secondhand smoke. Furthermore, the costs of legalizing marijuana would outweigh the tax revenues that legal weed would generate. So, in the end, legalizing cannabis may do more harm than good.

The Black Market and Marijuana Legalization

While a lot of people believe that legalizing marijuana will lead to a decrease in weed sold on the black market, law enforcement officers believe that the legalization of marijuana may even result in the expansion of the black market. Illegal drug cartels will be able to undercut the prices of state-licensed sellers of legal marijuana, leading to an even worse problem.

Marijuana Is Addictive and Legalization May Lead To an Increase in Cannabis Addiction

According to research done by the National Institute on Drug Abuse, 30% of marijuana users may have some degree of marijuana use disorder. A statistical analysis by the CDC showed that 48.2 million people in the US (about 18% of Americans) used cannabis at least once in 2019, and the data suggests that 3 in 10 marijuana users have a marijuana use disorder, while the number is even higher in youths under 18 who use cannabis. 

Final Thoughts on the Legalization of Marijuana

The use of marijuana is becoming more popular all around the US and with it the number of proponents for marijuana legalization. While there’s no doubt as to whether weed has medicinal benefits for some people, there are a wide number of repercussions that might come from legalizing weed. More research is needed to confirm whether the reasons we mentioned are valid, and in the states where weed is already legal, only time will tell whether the benefits of legalizing marijuana outweigh the risks. 

A passionate advocate for the benefits of cannabis. Fraser Horton, who has a background in botany and a strong love of nature, has spent years researching how cannabis affects the body and mind. He established Leaf Nation in 2020, where he has devoted himself to educating people about the legalisation of marijuana and its safe and responsible use. Fraser is committed to highlighting cannabis’ potential for improving wellness and working to dispel the stigma associated with its use.


The information presented on this page is provided as a public service to aid in education and is derived from sources believed to be reliable. Readers are responsible for making their own assessment of the topics discussed here. In no event shall Leaf Nation be held reliable for any injury, loss or damage that could happen if using or abusing drugs.