Cannabis Effects On Stroke Patients: What You Need To Know

Cannabis use has been linked to an increased risk of heart attack and stroke, with frequent cannabis smoking significantly increasing the likelihood of cardiovascular events. While the exact mechanisms are unclear, multiple factors could be responsible, including toxins released when the drug is burned and the presence of endocannabinoid receptors in the cardiovascular system. Research suggests that different cannabinoids, like THC and CBD, could have several benefits following a stroke, but most studies to date are animal experiments rather than human clinical trials.

Cannabis use and the risk of stroke

Cannabis use has been linked to an increased risk of stroke, with some studies reporting a positive association between the two and others finding no such link. However, the evidence is growing that cannabis consumption, especially through smoking, may be a risk factor for cardiovascular disease, of which stroke is a major component.

Cannabis and Stroke Risk Factors

A 2020 study found that cannabis users who had been admitted to hospital and screened positive for the drug through a urine test were more likely to be male, younger, and current smokers than those who tested negative. However, after adjusting for other factors that affect stroke risk, such as age, high blood pressure, high cholesterol, obesity, diabetes, smoking, and heart conditions, there was no link between recent cannabis use and an increased or decreased risk of stroke.

Cannabis Use and Cardiovascular Disease

Several studies have found a positive association between cannabis use and cardiovascular disease, which is the leading cause of death in the United States. An observational study of 435,000 American adults found that daily cannabis use was associated with a 25% increased likelihood of heart attack and a 42% increased likelihood of stroke when compared to non-use of the drug. The risk of cardiovascular events was also higher for weekly users, who showed a 3% increased likelihood of heart attack and a 5% increased likelihood of stroke.

Cannabis and Ischemic Stroke

Ischemic stroke, caused by a blockage in a blood vessel, has been specifically linked to cannabis use in several studies. A 2013 study of 218 New Zealanders with ischemic stroke or transient ischemic attack (TIA) found that 15.6% had urine drug screens (UDS) positive for cannabis, compared to 8.1% of control participants. After adjusting for tobacco use, an association independent of tobacco could not be established. However, a 2022 review of 17 studies involving 3,185,560 people with cannabis use found that the prevalence of ischemic stroke was 1.2%, higher than the 0.8% prevalence in people without cannabis use.

Cannabis and Recurrent Stroke

There is also evidence to suggest that cannabis use may be linked to recurrent stroke. A 2022 study found that among hospitalized adults ages 18-44 who had a history of stroke or TIA, the cause of another hospitalization was 48% more likely to be another stroke if they were habitual marijuana smokers. This was particularly true for young marijuana users who have a history of stroke or TIA and remain at significantly higher risk of future stroke.

While the exact mechanisms linking cannabis to heart disease and stroke are unclear, the evidence suggests that cannabis use may be a risk factor for stroke, especially in younger people. Further research is needed to establish a causal relationship and to understand the impact of various doses, duration, and forms of cannabis use on stroke risk.

THC's impact on the cardiovascular system

THC, or tetrahydrocannabinol, is the primary psychoactive ingredient in cannabis. It interacts with two receptors, CB1 and CB2, which are also widely distributed in the cardiovascular system. THC's impact on the cardiovascular system is extremely worrisome and likely needs more attention due to the growing legalization of cannabis for medicinal and recreational use.

THC causes an acute, dose-dependent increase in blood pressure and heart rate. There is evidence to suggest that increased frequency of marijuana use increases the risk of cardiac arrhythmias and myocardial infarction. Furthermore, chronic THC use has been associated with increased angina frequency, likely due to a decrease in the angina threshold, diminished sympathetic and parasympathetic nervous system signal transduction, serum aldosterone increases, central and peripheral vasoconstriction, and hypertension.

THC has also been shown to activate platelets via CB1 and CB2 receptors, leading to increased GPIIb-IIIa expression and activation of factor VII, a potent thrombogenic protein. A form of arteritis linked to marijuana use seems to differ from thromboangiitis obliterans (Buerger's disease) associated with smoke inhalation. Consumption of marijuana has been identified as a trigger for acute myocardial infarction. Risk of onset is increased 4.8 times over baseline in the 60 minutes after drug use, confirming the temporal relationship between cannabis and vascular events.

The widespread public perception of safety accompanying marijuana use has contributed to its increased use among the elderly, who are the most at-risk population for acute cardiovascular events.

Cannabis's potential benefits for stroke patients

Cannabis has been used for its psychoactive properties for thousands of years. In recent years, its medicinal properties have also been explored, including its potential to improve stroke symptoms and reduce cardiovascular risk factors.

Cannabis as a Neuroprotectant

The U.S. Government holds a patent (U.S. Patent No. 6630507B1) stating that cannabis acts as a neuroprotectant following an ischemic stroke. This patent was filed after a study performed on rats showed a 50% reduction in infarction size in the animals treated with cannabidiol (CBD). This is a significant result when compared to other drugs, which show no greater than a 2% reduction in infarction.

Cannabis's Effect on Blood Flow

Some studies suggest that cannabis can improve blood flow and reduce inflammation, which may be beneficial in treating ischemic events. A 2011 study published in the British Journal of Pharmacology indicated that 2-AG, an endogenous cannabinoid similar to THC, decreased brain edema, inflammation, and infarct volume, and improved clinical recovery in rats.

The Endocannabinoid System and Stroke

The endocannabinoid system is believed to play a role in the body's response to a stroke. After a stroke, cannabinoid receptors CB1 and CB2 become more active, and the release of beneficial endocannabinoids increases. Additionally, cannabinoids work to protect nerve cells from damage by activating CB and 5HT1A (serotonin) receptors.

Research suggests that cannabinoids like THC and CBD could have several benefits for stroke patients, including:

• Acting as a neuroprotectant
• Improving blood flow
• Reducing inflammation
• Protecting nerve cells from damage

However, it is important to note that most studies on the effects of cannabis on stroke are animal experiments, and more human clinical trials are needed to fully understand the potential benefits and risks.

The link between cannabis and ischemic stroke

Cannabis has been used for its psychoactive properties for thousands of years. The primary psychoactive ingredient of cannabis is delta(9)- tetrahydrocannabinol (THC). THC interacts with two receptors, the CB1 and the CB2, in the central nervous system (CNS).

There is evidence that cannabis use is associated with an increased risk of ischemic stroke (IS). A 2008 survey found that over 15 million Americans use cannabis regularly. A study of 218 New Zealanders with IS or transient ischemic attack (TIA) found that 15.6% had urine drug screens (UDS) positive for cannabis, compared to 8.1% of control participants. A review of literature by Wolff et al. revealed 59 case reports of cannabis-related stroke, with the majority being IS (83%). The mean age in this group was 33 years, and the ratio of men to women was 4.9 to 1. In a case study of 17 IS patients who were exposed to marijuana, the causal relationship was justified by the absence of other vascular risk factors, a temporal link between symptom onset and cannabis exposure, and the recurrence of symptoms with re-exposure. Another literature review by Desbois et al. noted 71 cases of cannabis users with IS. All patients were 'heavy' marijuana smokers, and 76.5% experienced acute symptoms during or within 30 minutes of consuming the drug.

The mechanism by which cannabis may cause IS is not yet fully understood, but there are several theories. THC may trigger reversible cerebral vasoconstriction syndrome (RCVS), and animal studies have shown that THC has peripheral vasoconstrictor properties. Cannabis consumption has also been identified as a trigger for acute myocardial infarction (MI), with a 4.8 times higher risk of onset in the 60 minutes after drug use. This confirms the temporal relationship between cannabis and vascular events.

However, the link between cannabis and IS is still under debate, with some studies finding no increased risk. A study from the University of Mississippi found no evidence for a connection between cannabis and ischemic stroke, with 1,643 out of 9,350 patients testing positive for cannabis. After adjusting for other factors that affect stroke risk, such as age, high blood pressure, high cholesterol, sickle cell disease, obesity, diabetes, smoking, and heart conditions, there was no link between recent cannabis use and an increased or decreased risk of stroke.

While the exact mechanisms linking cannabis to heart disease are unclear, multiple factors could play a role. In addition to toxins released when cannabis is burned, endocannabinoid receptors are widespread in the body's cardiovascular tissues and might facilitate heart risks.

The legality of cannabis

Three United Nations treaties regulate policies in most countries: the 1961 Single Convention on Narcotic Drugs, the 1971 Convention on Psychotropic Substances, and the 1988 Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances. Cannabis was reclassified in 2020 to a Schedule I-only drug under the Single Convention treaty, which means that while countries can allow its medical use, it is considered an addictive drug with a serious risk of abuse.

Countries that have legalised the recreational use of cannabis include Canada, Georgia, Germany, Luxembourg, Malta, Mexico, South Africa, Thailand, and Uruguay. In the United States, 24 states, 3 territories, and the District of Columbia have legalised its recreational use, and it is decriminalised in another 7 states. Commercial sale of recreational cannabis is legal nationwide in Canada, Thailand, and Uruguay, and in all subnational U.S. jurisdictions that have legalised possession except Virginia and Washington, D.C.

A policy of limited enforcement has also been adopted in many countries, particularly in the Netherlands, where the sale of cannabis is tolerated at licensed coffee shops.

Countries that have legalised the medical use of cannabis include Albania, Argentina, Australia, Barbados, Brazil, Canada, Chile, Colombia, Costa Rica, Croatia, Cyprus, the Czech Republic, Denmark, Ecuador, Finland, Georgia, Germany, Greece, Ireland, Israel, Italy, Jamaica, Lebanon, Luxembourg, Malawi, Malta, Mexico, the Netherlands, New Zealand, North Macedonia, Norway, Panama, Peru, Poland, Portugal, Rwanda, Saint Vincent and the Grenadines, San Marino, South Africa, Spain, Sri Lanka, Switzerland, Thailand, Ukraine, the United Kingdom, Uruguay, Vanuatu, Zambia, and Zimbabwe. In the United States, 38 states, 4 territories, and the District of Columbia have legalised the medical use of cannabis, but at the federal level, its use remains prohibited.

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