Marijuana Post-Stroke: What You Need To Know

Marijuana, or cannabis, has been used for its psychoactive properties for thousands of years. However, its therapeutic benefits have not been conclusively established, and there is evidence of harmful effects, including an increased risk of stroke. Research has found that marijuana use is associated with a higher risk of heart attack and stroke, with the risk increasing with the volume and frequency of use. Specifically, marijuana use has been linked to ischemic stroke and hemorrhagic stroke, with a prevalence of 1.2% and 0.3%, respectively, among cannabis users. Recent studies have also shown that marijuana use within 3-30 days before a rare type of bleeding stroke, called an aneurysmal subarachnoid hemorrhage, can more than double the likelihood of developing a serious complication, increasing the risk of death and disability.

Marijuana and the risk of stroke

The psychoactive properties of marijuana, derived from the cannabis plant, have been exploited for thousands of years. While some proponents of marijuana claim that it is "safer than tobacco", there is evidence to suggest that it has harmful effects.

The Science

The primary psychoactive ingredient in marijuana is delta(9)-tetrahydrocannabinol (THC). THC interacts with CB1 and CB2 receptors, which are distributed throughout the body, including the cardiovascular system. Activation of these receptors can modulate the cellular activity of the vessel wall, contributing to the pathogenesis of atherosclerosis.

The Evidence

Several studies have found a link between marijuana use and an increased risk of stroke, particularly ischemic stroke. A 2008 survey found that out of 218 New Zealanders with ischemic stroke or transient ischemic attack (TIA), 15.6% had tested positive for cannabis use. Another study of 3,185,560 people with cannabis use found that 1.2% experienced ischemic stroke, compared to 0.8% in those without cannabis use.

The mechanism by which cannabis causes stroke is not fully understood, but it may be related to the development of atherosclerosis or reversible cerebral vasoconstriction syndrome (RCVS). Animal studies have shown that THC has peripheral vasoconstrictor properties.

The Bottom Line

While the exact mechanisms are not yet clear, there is growing evidence of a link between marijuana use and an increased risk of stroke, particularly with more frequent use. This is particularly important to consider given the increasing legality and accessibility of marijuana. As such, it is recommended that healthcare practitioners assess cannabis use during patient encounters to discuss potential cardiovascular risks and ways to reduce them.

The impact of THC on the body

Central Nervous System

THC binds to cannabinoid receptors in the brain, particularly the CB1 and CB2 receptors. This interaction leads to changes in neurotransmitter release, resulting in the "high" associated with cannabis use. THC triggers the release of dopamine, leading to a pleasant euphoric feeling. It can also distort perception, induce relaxation, and enhance sensory experiences. However, THC can impair judgement, memory, and coordination, making activities like driving unsafe. In some cases, THC may trigger anxiety, paranoia, or even acute psychosis.

Cardiovascular System

THC can cause an increase in heart rate, dilation of blood vessels, and fluctuations in blood pressure. It has been linked to an increased risk of cardiovascular issues, including stroke, heart attack, and arrhythmias, especially in older individuals with existing cardiovascular conditions. THC may also contribute to the development of atherosclerosis and trigger reversible cerebral vasoconstriction syndrome (RCVS).

Respiratory System

The smoke from cannabis contains toxic chemicals, including ammonia and hydrogen cyanide, which can irritate the bronchial passages and lungs. Regular cannabis smoking can lead to respiratory issues such as bronchitis, chronic cough, and increased risk of lung infections. There is also a potential link between cannabis smoke and an increased risk of lung cancer, although more research is needed.

Eyes

THC causes blood vessels in the eyes to expand and fill with blood, resulting in the characteristic bloodshot eyes associated with cannabis use. Additionally, THC can lower intraocular pressure, providing temporary relief from glaucoma symptoms.

Gastrointestinal System

THC is known to increase appetite, commonly referred to as "the munchies." However, in some individuals, long-term heavy cannabis use can paradoxically cause nausea and vomiting. It has also been associated with gastrointestinal issues such as cannabinoid hyperemesis syndrome (CHS), acid reflux, and peptic ulcer disease.

Immune System

Animal studies suggest that THC may suppress the immune system, potentially increasing susceptibility to infectious diseases. However, this effect may benefit individuals with autoimmune conditions by reducing overactive immune responses.

The link between marijuana and heart disease

Marijuana use has been linked to a higher risk of heart disease and stroke, with studies finding that regular marijuana smokers have a 25% higher chance of having a heart attack and a 42% higher chance of having a stroke. The primary psychoactive ingredient in marijuana, delta(9)- tetrahydro-cannabinol (THC), interacts with CB1 and CB2 receptors, which are also found in the cardiovascular system. Activation of these receptors can modulate the cellular activity of the vessel wall, contributing to the pathogenesis of atherosclerosis and increasing the risk of acute myocardial infarction (MI).

The Hemodynamic Effect

One of the main reasons that cannabis may cause a stroke or heart disease is through what is called the hemodynamic effect, where cannabis causes the blood vessels to constrict. This can lead to a disruption in psychomotor behaviour, short-term memory impairment, stimulation of appetite, and an increase in heart rate and blood pressure, all of which can increase the risk of a stroke.

Toxins in Smoke

Another reason for the link between marijuana and heart disease is the toxins found in the smoke, known as particulate matter. Similar to cigarette smoke, this contributes to the buildup of plaque in the blood vessels, increasing the risk of cardiovascular events such as heart attacks and strokes.

Age and Frequency

Age and frequency of use also play a role in the link between marijuana and heart disease. The risk is increased for both the general population and younger adults, with men under 55 and women under 65 still having an increased risk of heart disease, heart attack, or stroke. Additionally, the more frequently someone smokes marijuana, the higher their risk, with daily users having a higher chance of a heart attack or stroke than those who smoke less often.

Medical Benefits

While there are documented medical benefits to using cannabis, such as the potential to limit damage to nerve cells in the brain and prevent stroke, it is important to note that smoking marijuana can still increase the risks of stroke and heart disease, especially in younger adults.

The endocannabinoid system and cerebrovascular disease

The endocannabinoid system is a regulatory component of the cerebrovascular system, which is responsible for maintaining a continuous oxygen supply to the central nervous system (CNS). The system has two main homeostatic functions: adjusting the local blood supply to meet the metabolic demands of neurons and maintaining an optimal extracellular environment in the brain.

The endocannabinoid system consists of two cell-surface cannabinoid receptors, cannabinoid 1 (CB1R) and cannabinoid 2 (CB2R), as well as their endogenous ligands, known as endocannabinoids. CB1R is found in the CNS, as well as in peripheral neural and non-neural cells. CB2R is expressed in the CNS and cardiovascular, gastrointestinal, and immune systems.

The endocannabinoid system has been implicated in the regulation of cerebral circulation and has been shown to play a role in cerebrovascular pathologies such as subarachnoid hemorrhage, traumatic brain injury, and ischemic stroke.

In a rat model of stroke, CB1R knockout mice had larger infarct volumes, worse neurological deficits, decreased cerebral blood flow, and increased N-methyl-D-aspartate (NMDA) excitotoxicity compared to wild-type mice. This suggests that the endocannabinoid system is intricately linked with neuronal and endothelial behavior.

CB2R agonists have been found to suppress neurodegeneration in rat models of ischemic stroke, while also reducing inflammation and leukocyte rolling. CB2R activation has also been shown to improve blood perfusion in the brain following ischemic injury.

However, the role of the endocannabinoid system in stroke is complex, and further research is needed to fully understand its therapeutic potential. For example, CB1R and CB2R double-knockout mice have shown improved post-stroke outcomes, suggesting that agonist activity at these receptors may drive deleterious physiological processes in the post-stroke brain.

In addition, the specific target of cannabidiol (CBD), a widely available cannabinoid, has yet to be established, and conflicting evidence exists regarding its neuroprotective effects in animal models of stroke.

Overall, the endocannabinoid system has been shown to play a significant role in cerebrovascular regulation and pathologies, but further research is needed to determine its full therapeutic potential in stroke treatment.

Medical marijuana and its potential benefits

Marijuana has been used for its psychoactive properties for thousands of years. The cannabis plant contains more than 100 different chemicals, known as cannabinoids, each with a different effect on the body. The two main chemicals used in medicine are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is responsible for the “high” associated with marijuana consumption, while CBD is non-intoxicating and non-euphoric.

Medical marijuana is used to treat a broad range of symptoms and conditions, including severe and chronic pain, multiple sclerosis, severe nausea and vomiting caused by cancer treatment, epilepsy, seizures, extreme weight loss, irritable bowel syndrome, and post-traumatic stress disorder.

Pain Relief

Marijuana is commonly used for pain control, especially for the chronic pain that plagues millions of people, particularly as they age. It is safer than opiates, as it is impossible to overdose on and is far less addictive. It can also be a substitute for NSAIDs such as Advil or Aleve, which some people cannot take due to kidney problems, ulcers, or GERD.

Nausea and Weight Loss Management

Medical marijuana can help manage nausea and weight loss, particularly in people with HIV/AIDS. It can increase appetite and reduce weight loss, improving the overall health of the patient.

Muscle Relaxation

Marijuana is said to be an excellent muscle relaxant, helping to reduce tremors in people with Parkinson's disease. It has also been used successfully for fibromyalgia, endometriosis, interstitial cystitis, and other conditions where the final common pathway is chronic pain.

Treatment of Seizure Disorders

Medical marijuana has received attention for its ability to control seizures, particularly in children with rare seizure disorders like Lenox-Gastaut and Dravet syndromes. The FDA has approved Epidiolex, a drug made from a purified form of CBD, for the treatment of these rare seizure disorders.

Lowering Blood Pressure

A 2017 study by JCI Insight found that CBD lowered the blood pressure of human participants, both at rest and after stress tests. This suggests that medical marijuana could be beneficial for people with high blood pressure or cardiovascular issues.

Reducing Inflammation

According to a study by the Rockefeller Institute of Medical Research, CBD has been proven to help reduce inflammation and the neuropathic pain it can cause. This makes it a potential treatment option for people with inflammatory conditions.

Preventing Relapse in Drug and Alcohol Addiction

A 2018 study found that CBD can be useful in helping people with drug and alcohol addiction by reducing stress-induced cravings, anxiety, and lack of impulse control that often lead to relapse.

Treating Anxiety Disorders

Anxiety is a common reason for CBD use, and studies have found that it could be effective in treating generalized anxiety disorder, panic disorder, social anxiety disorder, obsessive-compulsive disorder, and post-traumatic stress disorder.

Treating Gastrointestinal Disorders

Recent studies have found that CBD and other non-psychoactive cannabinoids can effectively prevent and treat gastrointestinal disorders such as irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), Crohn's disease, and ulcerative colitis. CBD's anti-inflammatory properties play a key role in reducing and preventing symptoms.

While medical marijuana has shown potential benefits in these areas, it is important to note that it may also have harmful effects, especially when smoked. Smoking marijuana can damage the lungs and increase the risk of stroke, heart disease, and blood vessel disease. Additionally, THC, the psychoactive component of marijuana, has been linked to an increased risk of certain types of strokes and serious complications. Therefore, it is crucial to carefully consider the potential benefits and risks before using medical marijuana, especially for individuals with existing health conditions.

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