cons for medical marijuana

Pros and Cons of Medical Marijuana

Angela Morrow, RN, BSN, CHPN, is a certified hospice and palliative care nurse.

Rochelle Collins, DO, is a board-certified family medicine doctor currently practicing in Bloomfield, Connecticut.

The debate over the therapeutic benefits of medical marijuana is ongoing. While a number of states in the U.S. have active medical marijuana laws (and a growing number allow recreational use), the federal government continues to classify it as a Schedule I controlled substance. Not only does that make it illegal to possess, but it also limits medical studies into the potential benefits of cannabis.

With strong supporters on each side of the debate, the arguments for and against the legalization of marijuana are hot topics. What are the debated pros and cons of medical marijuana?

The Pros

The legalization of marijuana for medical reasons is viewed favorably by many Americans, including members of the medical community and Congress. Some of the arguments for medical marijuana include:

  • Marijuana is effective in relieving nausea and vomiting. Studies have shown that pharmaceutical cannabis can decrease nausea caused by chemotherapy used to treat cancer and almost completely eliminate vomiting.  
  • Marijuana can relieve the spasticity of the muscles that is sometimes associated with multiple sclerosis and paralysis.
  • Marijuana can help treat appetite loss associated with conditions such as HIV/AIDS and certain types of cancers.
  • Marijuana can relieve certain types of chronic pain, including neuropathic pain.  
  • Marijuana is safer than some other medications prescribed to treat the same symptoms. For example, it may be used instead of opioids for pain management. Opioids are highly addictive and are typically not recommended for long-term use in treating chronic pain.  
  • Cannabis does not need to be smoked to be medically beneficial. Products such as cannabidiol (CBD) oils, topical pain relief treatments, edibles, and other non-smoking applications are now available.  
  • As research continues, more of the individual compounds in cannabis are being found to be beneficial. When isolated—such as CBD has been—these may lead to further advancements in medical treatment options without the “high” produced by the compound commonly known as THC.  
  • Marijuana has been used for centuries as a natural medicinal agent to good effect.

The Cons

For every person who advocates for the legalization of marijuana for medical purposes, there is another who argues against it. Some of the arguments from the opposition include:

  • Frequent marijuana use can seriously affect your short-term memory.  
  • Frequent use can impair your cognitive ability.
  • Smoking anything, whether it’s tobacco or marijuana, can seriously damage your lung tissue.  
  • Smoked marijuana contains cancer-causing compounds.
  • Marijuana carries a risk of abuse and addiction.
  • Marijuana has been implicated in a high percentage of automobile crashes and workplace accidents.
  • Marijuana is illegal under federal law. It is classified as Schedule I drug in the Controlled Substances Act (CSA), alongside heroin. This classification says that the substances have no currently accepted medicinal value.

Scientific Evidence Remains Limited

In the past, clinical trials to evaluate the effectiveness of marijuana to treat certain conditions have been restrictive and limited. As medical marijuana becomes more prevalent throughout the world, researchers are doing more studies.  

However, expert reviews of current research continue to advocate that more studies are needed. Many of the hurdles involve controlling the quality and dosing of cannabis with what is legally available to researchers. Additionally, a number of the current studies are not controlled clinical trials in which a placebo or alternative medicine is used.   Without more of these comparative studies, scientific evidence on the therapeutic effects of cannabis will remain in question.

Until marijuana is downgraded from a Schedule I drug, widespread clinical trials are unlikely to happen in the United States.

If we really want a definitive answer as to whether marijuana is valuable for symptom management, it needs to be evaluated using the same standards as other medications.

The debate over medical marijuana has many pros and cons. Explore the arguments and learn why more research is needed to understand its efficacy.

11 5.3: Pros and Cons of Medical Cannabis

After reading this section, you will be able to:

  • Understand the methods of cannabis administration
  • List the pros and cons of medical cannabis

The debate over the usage of cannabis as a therapeutic remedy remains ongoing, and scientists are hastily investigating its clinical benefits and detriments to settle the battle. Due to the presence of the ECS engraved in our nerve network, cannabis can have multiple effects on our bodies. It is well known for the euphoric effects that it can induce due to the presence of THC. However, it also contains other non-psychotropic compounds such as CBD and CBG which have been studied to be beneficial in combating disease. Arguably, cannabis’s interference on the nervous system can also do more damage than good by impairing certain regions in the brain that are needed to regulate bodily functions.

Few countries have legalized the use of cannabis for treating chronically ill patients. Canada and the Netherlands have government programs in which specialized companies supply qualitative and safe herbal cannabis for patient use. Cannabinoids can be administered orally in organic edible oils, inhaled as a vapor, applied topically, smoked, brewed in tea, or mixed in food. For clinical use, cannabinoids can be prescribed as nabilone capsules, dronabinol capsules, and oromucosal spray nabiximols.

However, many clinicians are unaware of the medical benefits of cannabis to authorize its use. Therefore, patients or caregivers seek illicit drugs, “street marijuana”, that may contain compositions of cannabinoids and other substances that are unsafe for the patient. To further understand the implications of cannabis, the debating pros and cons are reviewed.

The Pros

Pain Management

Cannabis may be a beneficial and safer alternative for pain management. Current emerging literature demonstrates beneficial properties of cannabinoid use for treating pain symptoms including cancer pain. A meta-analysis reported an average 30% pain reduction with cannabinoid use than placebo. This will be further discussed in Chapter 5.4.

Epileptic Seizures

Cannabis can help control epileptic seizures and possibly prevent occurrence. Growing pre-clinical evidence has shown beneficial factors for the use of cannabinoids in treatment of epilepsy. Several studies have demonstrated anti-convulsant properties of CBD and cannabidivarin, the propyl variant of CBD, in epileptic mouse and rat models. Furthermore, a prospective, single centered study reported that after CBD treatment, 72 children and 60 adults with treatment resistant epilepsy presented improvements in their illness.

Anti-Inflammatory Properties

Cannabis can also benefit patients with inflammatory bowel diseases such as Crohn’s disease and ulcerative colitis. C. sativa phytocannabinoids such as CBD can exert anti-inflammatory function by activating CB2 receptors. Additionally, they can promote wound healing through activation of CB1 receptors in the gut. Moreover, these compounds can decrease permeability of the intestine by blocking endogenous THC- like compounds to its receptors, thereby preventing bacteria entry.

Cannabis can also be used a potential prophylactic treatment against neurodegenerative diseases such as ALS and Alzheimer’s disease. CBD and CBG both exert anti- oxidative and anti-inflammatory properties that would protect neuron cells from cell damage. This property will be further discussed in Chapter 5.6.

Relief From Nausea and Vomiting

Some studies have demonstrated cannabis as an effective treatment in relieving nausea and vomiting. Due to the wide distribution of the ECS in the intestines, multiple C. sativa cannaibinoids can treat nausea and vomiting. In 1985, the FDA approved nabilone, a synthetic equivalent of D9-THC, as a treatment drug for chemotherapy- induced nausea and vomiting.


It is impossible to overdose from cannabis. It would require consumption of 15,000 joints in 20 minutes to receive toxic levels of THC!

The Cons

Impairment of Cognitive Function

Historically, it is well known that THC can have significant physical and psychological effects. Due to the ECS, it can directly target numerous regions of the brain that control cognitive function, thereby affecting basic motor coordination, the ability to plan, organize, solve problems, make decisions, and control emotions. Many studies have suggested a significant cognitive decline in cannabis abusers compared to a healthy control.

Impairment of Short-Term Memory

THC can alter the way information is processed and how memories are formed in the hippocampus, a region in the brain that is responsible for memory. There is evidence that supports that a high dosage of D9-THC impairs short term memory tasks. More importantly, cannabis use can create serious memory impairments in developing brains.


Cannabis users who have taking large dosages may experience periods of acute psychosis including hallucinations, delusions, and a loss of the sense of personal identity. Adolescent abusers are specifically at risk because it can affect neurodevelopment and dysregulate the ECS. This increases the risk of developing schizophrenia.

Trajectory for Medical Cannabis Use

Chronic diseases are increasing in prevalence and are impacting the quality of lives of patients and their fellow caregivers. Despite conventional drugs in treatment of disease, adverse effects can additionally harm the patient. Therefore, finding alternative solutions, such as cannabis to treat disease symptoms with low adverse effects, is essential in progressing treatment options. Although large emerging research has suggested benefits for cannabis use in numerous conditions, many continue to disapprove of its use due to psychosocial and emotional concerns. More research and debate are required to reach a consensus for the medical use of cannabis.

11 5.3: Pros and Cons of Medical Cannabis After reading this section, you will be able to: Understand the methods of cannabis administration List the pros and cons of medical