Introduction 

Sleep problems, though common, can be frustrating to deal with. Insufficient sleep can lead to fluctuating mood, low energy, and has been linked to a plethora of health issues. Thus, in an attempt to find a quick remedy, many people tend to turn to the sedating effect of cannabis. However, it is vital to take into consideration the effects cannabis can have on a sleep disorder such as sleep apnea. 

Sleep disorders are conditions that disturb your regular sleep pattern. One notable sleep disorder is sleep apnea. This condition can cause an irregular heartbeat, high blood pressure, and even strokes. Thus, to curb the deleterious effects of sleep apnea, this article delves into the potential effects of cannabis on the symptoms of sleep apnea. 

What is sleep apnea?

Sleep apnea is a severe sleep disorder characterised by breathing interruptions during sleep. This condition is highly prevalent in people with heart disease. This is because the disordered breathing associated with sleep apnea can trigger a cascade of complications such as oxidative stress, hypoxia, and endothelial dysfunction, all of which are risk factors for heart disease.¹ 

Sleep apnea occurs more frequently in men than women. Possible explanations for male predominance are the effect of hormones on the muscles of the upper airways, the gender differences in terms of the distribution of body fat, and the function and anatomy of the pharyngeal in males and females.² Obesity is a major risk factor of snoring and sleep apnea.² Additionally, other risk factors that predispose people to this condition include older age, smoking, alcohol intake, coronary artery disease, and hypertension.^3,4 In general, the prevalence of sleep apnea accompanied by excessive daytime sleepiness ranges from 13%-33% in men and 6%-19% in women. However, it can be higher in elderly groups or people with the above-mentioned risk factors.⁵

Types of sleep apnea 

These are the major types of sleep apnea;

• Obstructive sleep apnea (OSA): This is the most common and prevalent type of sleep apnea. This occurs when the muscles in your throat block the airway causing it to collapse and interfere with regular breathing.¹ The risk factors for this condition include obesity, family history, smoking, alcohol consumption, and certain health conditions
  Central sleep apnea: This is a less common type of sleep apnea that stems from a neurological condition. These conditions include chronic kidney disease, brain infection, stroke, etc. It occurs when the brain doesn’t send appropriate signals to the muscles that control breathing. It shares similar symptoms with OSA such as excessive daytime sleepiness and disrupted breathing during sleep
  Complex sleep apnea: This occurs as a combination of obstructive sleep apnea and central sleep apnea. It typically occurs in patients undergoing treatment for OSA known as CPAP therapy. One of the complications or effects of this therapy could be the development of symptoms associated with central sleep apnea

Symptoms of sleep apnea

The following are the symptoms of sleep apnea: 

• Dislaboured breathing during sleep
• Morning headache and dry mouth
• Insomnia
• Excessive daytime sleepiness
• Loud snoring
• Hypersomnia 
• Xerostomia 
• Attention deficits⁶ 

Understanding cannabis and its components

Cannabis, commonly known as marijuana, is a genus of flowering plants touted for a variety of benefits. These include medicinal, recreational, and for use in religious ceremonies, etc. This plant contains many chemical compounds. However, the two most scientifically-researched components of cannabis are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD).⁷ THC is responsible for the psychoactive and intoxicating properties while CBD is non-intoxicating and has been proven to alleviate a myriad of health conditions. These include a reduction in the frequency of seizures, chronic pain, post-traumatic stress disorder (PTSD), and insomnia.⁷

Recently, there has been a discovery of other types of cannabinoids produced by the body called endocannabinoids. These are produced in the brain and make up part of a complex biological system called the endocannabinoid system (ECS).⁸ The ECS is a widespread neuromodulatory system that helps to regulate and balance essential body functions. These functions include cognition and memory, motivation, sleep and arousal, pain, and various immune processes.⁹

The ECS comprises of 3 parts;

• Endogenous cannabinoids (endocannabinoids)
• Cannabinoid receptors (CB1 and CB2)
• Enzymes that synthesize and breakdown endocannabinoids⁸

 Endocannabinoids are those endogenous lipids naturally produced in the body that signal the cannabinoid receptors. These lipids partially mimic the effects and behavior elicited by the psychoactive components of cannabis (THC).⁸ The cannabinoid receptors respond to exogenous cannabinoids (i.e. THC and CBD).⁷ This implies that the effects of cannabis on the symptoms of sleep apnea are attributed to the neuromodulatory functions of the ECS which includes sleep regulation.⁸

How cannabis affects sleep 

Cannabinoids (endogenous and exogenous cannabinoids) are neurotransmitters that can bind to cannabinoid receptors (CB1 and CB2). Cannabinoid receptor 1 (CB1) is located in the central nervous system (i.e. the brain and spinal cord) where it controls sensory, motor, and emotional responses.⁷ Cannabinoid receptor 2 (CB2) is located in the peripheral nervous system and is vital in maintaining immune function.¹⁰

Thus, the effects of cannabis on sleep (exogenous cannabinoids) are attributed to their interactions with the cannabinoid receptors and the neurotransmitters in the brain.⁷ When cannabinoids bind to CB1 receptors, they trigger the increase of sleep-promoting adenosine and obstruct the brain’s arousal system. Many neurotransmitters are affected by cannabinoids but the most notable are gamma-aminobutyric acid (GABA), serotonin, and dopamine.⁷ GABA is an inhibitory neurotransmitter found in the brain that provides your nervous system with a calming effect. Cannabis (CBD) can act on GABA receptors and enhance GABA reuptake. This can alleviate some symptoms associated with sleep apnea such as insomnia, attention deficits, and hypersomnia.⁸

The two main active compounds in cannabis are THC and CBD and can affect sleep in different ways. This is also depending on the quantity and how it is taken. For instance, low doses of THC can improve sleep and high doses can make it worse, while the reverse is the case for CBD.¹¹ Additionally, heavy use of THC can cause somnolence and paranoid behavior.⁷

Potential effects of cannabis on sleep apnea symptoms

The main components of cannabis (THC and CBD) exert opposite effects on sleep which depends on the concentration and how it is taken. However, these exogenous cannabinoids exert the following effects on sleep apnea symptoms;

• Effects of cannabis on dislaboured breathing: The neurotransmitter serotonin exerts an excitatory effect on the motor neurons in the upper airways which is essential in maintaining an unobstructed upper airway and reducing apnea. THC has an agonist effect on serotonin receptors and can facilitate the reuptake of serotonin. Consequently, this modulates the muscles of the upper airways which are responsible for regulating breathing during sleep¹²
  Effects of cannabis on excessive daytime sleepiness: THC can affect excessive daytime sleepiness depending on the quantity. Although cannabinoids are associated with inducing daytime sedation, this depends on the amount and method of administration. For instance, 15mg of THC was found to be sedating, whereas 15mg of CBD increased wakefulness and counteracted the sedating effect of THC¹¹
  Effects of cannabis on insomnia and hypersomnia: Cannabis induces a quick onset of sleep leading to decreased insomnia and hyperinsomnia. However, it can disrupt the deep stages of sleep, particularly rapid eye movement (REM) sleep. This is associated with chronic use¹³
  Effects of cannabis on xerostomia and attention deficits: Dry mouth or xerostomia has been associated with the use of cannabis. This is because THC activates the CB1 receptors of the submandibular gland to limit the production of saliva. Contrarily, THC improves ADHD symptoms due to its effects on GABA receptors⁷ 

Risks associated with the use of cannabis for sleep apnea

As cannabis is an intoxicating substance, the following are the risks associated with its use for sleep apnea;

• Risk of dependence due to long-term use: As many people turn to cannabis to alleviate the symptoms associated with sleep apnea, there is a potential risk of dependence which is mostly psychological.¹³ This could lead to fear or anxiety about sleep as the person could be saddled with the belief that sleep is impossible without cannabis
• Cardiovascular complications and abnormal brain activity¹³
• Effect on circadian sleep-wake rhythm: Cannabis can alter the perception of time especially in people that use it for recreation purposes. This could have a profound impact on the normal sleep-wake cycle and trigger the development of other sleep disorders¹³
• Effect of cannabis withdrawal on sleep: This is perhaps the most severe symptom of withdrawal from the use of cannabis. Consequently, this could trigger alcohol or other drug use, or relapse to cannabis use¹⁴

Summary 

• Cannabis is a psychoactive substance popularly known for it recreational use and is made up of hundreds of components. The most notable ones are THC and CBD
• This substance has been touted for a range of benefits such as medicinal, anti-emetic, appetite-modulating, and analgesic properties
• Sleep apnea is a chronic sleep disorder characterized by disordered breathing during sleep with potential life-long complications if unmanaged
• Cannabis affects sleep mainly through the interaction of cannabinoids with the cannabinoid receptors in the brain and its influence on the brain neurotransmitters
• Cannabis improves some of the symptoms associated with sleep apnea. However, this is largely dependent on the amount and the form it is used
• There are risks of dependence, withdrawal problems, and interruption of the normal sleep cycle associated with the use of cannabis and its derivatives
• Therefore, long-term use is not advised with the use of cannabis to reduce the occurrence and severity of potential future complications

FAQs

What are the causes of sleep apnea?

Both modifiable and non-modifiable factors can trigger the development of sleep apnea. This includes obesity, age, family history, medical conditions, drug use, smoking, and alcohol intake. 

How is sleep apnea diagnosed?

Signs that suggest a diagnosis of sleep apnea include snoring, breathing difficulties during sleep, and snoring. However, the best and most reliable diagnosis involves an overnight sleep study. This measures your sleep, breathing, and oxygen levels and is usually done by the general practitioner. 

Is sleep apnea dangerous? 

Yes, sleep apnea can be dangerous if left untreated for a long time. People with sleep apnea don’t have quality sleep, hence, they often have concentration issues and extreme tiredness. This can put them at risk for car accidents or problems at work. Most importantly, the long-term complications of sleep apnea involve the cardiovascular system and increase the risk of heart attacks, high blood pressure, and even heart failure.