First, let’s retrace the origins of cannabis. We’ll then look more specifically at the effects and risks of cannabis consumption, and in particular its interaction with diabetes.

The properties of hemp

Cultivated for its strong fibers, nourishing seeds and medicinal properties, hemp is an annual plant with 4,000 varieties. The plant has been widely used in the past, and is still used today, for its many applications: fabric, rope, fuel, paper, oil, food and feed… In Canada, hemp cultivation has been authorized since 1998 and is strictly regulated and inspected by Health Canada. Hemp is grown in Saskatchewan, Manitoba and Alberta.

What’s the connection between hemp and cannabis?

Hemp and cannabis refer to the same botanical species, Cannabis Sativa L. The term hemp refers to the industrial plant and its plant fiber, while cannabis is the scientific name for the psychoactive form used as a recreational drug or for medical purposes. Cannabis is known for its euphoric effect when dried. It’s the concentration of delta-9-tetrahydrocannabinol (THC) that differentiates industrial or agricultural hemp from cannabis. Industrial hemp contains less than 0.3% THC, while recreational hemp contains over 5%, depending on the species. There are several subspecies of Cannabis Sativa L., the main ones being sativa and indica. Cannabis sativa has a stimulating, euphoric effect, while cannabis indica provides a feeling of relaxation.

What’s the difference between cannabis, marijuana and hashish?

The term cannabis refers to the whole plant. Marijuana is made up of the upper leaves, flowers and seeds of the cannabis plant. These components are dried, finely chopped and smoked as is or mixed with tobacco. Marijuana can also be used for baking. Its THC content varies, reaching up to 30% depending on where it comes from and how it is prepared. Hashish is a paste made from the flowers of the cannabis plant, with a THC content of up to 60%.

The composition of cannabis

Cannabis is a so-called natural drug, but that doesn’t mean it’s harmless. It is composed of over 500 different substances, the main ones being delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). These chemical compounds are known as cannabinoids.

Delta-9-tetrahydrocannabinol (THC)

THC is the main active ingredient that produces, among other things, a euphoric effect. The higher the THC concentration in a product, the greater its harmful effects. Over the past 30 years, new cultivation methods and plant selection have evolved. As a result, the THC concentration of cannabis has risen from an average of 1% in 1960 to at least 12% in 2015. THC activates the body’s internal system of specific receptors that affect memory, motor coordination and the immune system, among other things. THC is responsible for the way our brains react to cannabis (the famous high). THC also acts on the brain receptors responsible for controlling food intake. It is a powerful appetite stimulant.

Cannabidiol (CBD)

CBD, another cannabinoid, does not produce a euphoric effect. It can block or reduce some of the effects of THC if the quantity present in cannabis is equal to or greater than THC. It is studied mainly for its potential therapeutic uses.

The legalization of cannabis

Recreational use of cannabis is now authorized in Canada. Canada becomes the first G7 country to vote to legalize cannabis. The aim is to control the production, distribution, sale and possession of cannabis throughout Canada. The government wants to reduce the risks associated with illegal cannabis use, because :

  • It is impossible to assess the THC content of cannabis on the black market.
  • The quality and purity of illegal cannabis cannot be guaranteed.
  • Cannabis is often mixed (“cut”) with other substances to increase its volume and weight, and therefore its price. These substances may be pesticides, other drugs or heavy metals such as lead. You may also want to improve its appearance if it’s of poor quality. In such cases, vegetable gums, henna, black shoe polish or tire oil are used.
  • All these additives carry serious risks of intoxication and respiratory damage.

To find out more about the laws relating to cannabis, consult the Cannabis Act, the Act respecting the Société des alcools du Québec and the Amendment to the Highway Safety Code.

Prescribing cannabis for medical purposes

Health Canada has authorized two pharmacological treatments whose chemical structure is similar to cannabis. These are medical cannabinoids:

  • Nabilone (Cesamet) tablets are reimbursed by the Régie de l’assurance maladie du Québec (RAMQ). It is approved for the treatment of chemotherapy-induced nausea and vomiting;
  • THC/CBD (Sativex) comes in an oral atomizer (vaporizer) and is reimbursed as an exception drug by the RAMQ. It is used, among other things, to relieve spasticity and neuropathic pain in people with multiple sclerosis.

In 2015, the Ministry of Health listed Cesamet and Sativex for the management of neuropathic pain. Taking these cannabinoids should be complementary to the basic prescription of anti-inflammatory and opoid drugs (e.g. codeine, oxycodone, morphine) when the latter do not effectively relieve pain.

The health risks of cannabis use

Knowledge about cannabis and its impact on health remains a developing subject. The majority of people who use cannabis do not suffer any negative consequences. However, this does not mean that cannabis use should be trivialized.

Risks to cognitive ability

The health risks and negative consequences of cannabis use stem in particular from its effects on a person’s cognitive abilities, such as judgment, attention, memory and decision-making.

These effects can sometimes have repercussions on a person’s daily activities, for example: driving, work, learning situations and other situations involving gestures or actions requiring coordination and speed.

For teenagers, high consumption at an early age can impair brain development. It is advisable to consume as little as possible during this period, particularly before the age of 16.

For regular users of large quantities of cannabis (5 joints or more per week), it is possible to observe :

  • Decreased memory (immediate and delayed), attention and concentration;
  • Decreased ability to organize, integrate and process complex information.

Some cognitive problems may persist for a few weeks after cessation of consumption, but are reversible even in heavy users.

Physical health risks

Cannabis use can amplify existing health problems, such as certain chronic illnesses:

  • Cannabis use increases heart rate and can alter its rhythm.
  • Consumption causes a rise in blood pressure.
  • Inhalation of cannabis smoke can aggravate existing respiratory illnesses, and even promote their onset.

Cannabis use by people with type 2 diabetes is also associated with an increased risk of peripheral arterial occlusion and myocardial infarction. The risk of developing kidney problems is also higher in cannabis users, whether living with type 1 or type 2 diabetes.

Mental health risks

Cannabis use carries mental health risks. It can cause :

  • Depressive symptoms;
  • Anxiety;
  • Psychotic symptoms, such as hallucinations or paranoid ideas (in most cases, these symptoms are limited to the period of intoxication and cease on their own);
  • Withdrawal symptoms following dependence, which can occur in 9% of adults who use marijuana recreationally.

In people with pre-existing mental health problems, cannabis use may exacerbate the illness or cause psychosis and/or depression.

Risks of combining with other substances

Alcohol

Consumed separately, alcohol and cannabis have harmful effects, but taken together they are even more dangerous, especially when driving.

A Canadian study in 2000 showed that as cannabis use increased, so did alcohol consumption. The psychotropic effects of cannabis are amplified because alcohol consumption causes THC to be absorbed more rapidly. What’s more, mixing alcohol and drugs increases the risk of psychotic experiences in vulnerable individuals, as well as nausea and vomiting.

Medicines

Cannabis can influence the effect of prescription or over-the-counter medications you’re already taking. Or certain medications may have an impact on the effects of cannabis. It is therefore essential to discuss any decision to use cannabis with your pharmacist.

The adverse effect of marijuana use on appetite

In 1970, researchers began studying the effect of THC on eating habits. The results were clear from the outset: volunteers treated with this molecule craved sweets and fats much more, had a bigger appetite and enjoyed food more.

Since then, several studies have confirmed this effect in humans and numerous animal models. In rats, the action of THC is so powerful that it induces them to eat even when they are force-fed.

Duration of cannabis effects

The effects of cannabis are not the same and do not last the same for everyone. This can vary according to the type and species of cannabis consumed, the amount of THC versus CBD, the quantity of cannabis consumed, and the method of consumption.

With smoked cannabis, the active components in the smoke pass from the lungs into the bloodstream, reaching a peak after 15 minutes. Effects last from 1 to 4 hours.

The effects of cannabis mixed with food appear after around 60 minutes. Its effect can last from 6 to 8 hours. There is a risk that the person will eat more of the food, as the euphoric effect is delayed and the person may think that the cannabis is not potent.

It’s important to point out that this is the duration of the acute effects of cannabis. There are also longer-lasting effects, notably on memory, attention and motivation, which last at least until consumption ceases. Whether these effects persist beyond the point of permanent cessation is a matter of controversy.

Overall, a single dose of THC produces effects lasting approximately forty-five minutes. If several doses are taken over a period of one hour, the effects perceived by the user will cease approximately two and a half hours after consumption.

Cannabis use and diabetes

Positive effects to be confirmed

There are very few studies on the effects of cannabis on diabetes. We can expect an increase in research following the legalization of cannabis.

Pain relief associated with neuropathy

Cannabis may be effective in relieving diabetic neuropathy. This relieving effect would be associated with CBD and not THC. However, few studies have been carried out on the subject, and these have been of short duration and involved few participants. More studies are therefore needed before recommending CBD for the relief of diabetic neuropathy.

Increased insulin sensitivity in people living with type 2 diabetes

According to an American study published in 2013, cannabis consumption is thought to increase insulin sensitivity in people living with type 2 diabetes. This effect could be linked to a lower body mass index and better carbohydrate metabolism in users. Again, further studies are needed to confirm or refute these findings.

Negative effects to consider

If cannabinoids affect the metabolic system, insulin sensitivity and appetite, it’s also possible that frequent cannabis use disrupts these same functions and produces these adverse effects:

Increased blood sugar levels

The main disadvantage of cannabis use in people living with diabetes is increased appetite following consumption. Cannabis use is associated with increased cravings for sweet and/or high-fat foods. The greater consumption of sweets leads to a rapid rise in blood sugar levels, which is problematic for people living with diabetes. Very high blood sugar levels can lead to medical emergencies.

This increase in appetite can also lead to weight gain, especially if consumption is frequent, which is not desirable in people living with diabetes.

More difficult to manage blood sugar independently

Cannabis use is generally associated with poorer maintenance of blood sugar levels within the target range. The risk of hyperglycemia is higher due to cravings, but there is also an increase in glycated hemoglobin in people with type 1 diabetes who use cannabis. The risk of hypoglycemia in people with diabetes is similar whether cannabis is used or not. However, cannabis can reduce the perception of hypoglycemia.

Increased risk of diabetic ketoacidosis

Moderate cannabis use in people with type 1 diabetes is associated with an almost doubled risk of diabetic ketoacidosis. This is due to a rise in blood sugar levels associated with increased appetite. Cannabis use can also induce vomiting in some people, which can lead to dehydration and the development of DKA, even if blood sugar levels are within the normal range.

Recommendations

Several recommendations can be made regarding cannabis use by people living with diabetes.

Firstly, cannabis use is not recommended for adolescents and adults living with diabetes, as no safety benefits have yet been demonstrated, and because its use is associated with poorer self-management of diabetes. More specifically, in people with type 1 diabetes, cannabis use is associated with the additional risk of diabetic ketoacidosis. Cannabis use should therefore be avoided in people with type 1 diabetes, to limit the risk of diabetic ketoacidosis.

No use is preferable, but if you do use cannabis, here are some suggestions:

  • Reduce cannabis consumption gradually
  • Decrease the amount of cannabis per consumption
  • Increase the time between uses of cannabis
  • Reduce tobacco consumption. Tobacco reduces the effects of cannabis, which can lead to an increase in cannabis consumption to achieve the same effects.

Finally, if you do use cannabis, don’t hesitate to discuss it with your health-care team. This will enable your doctor and other members of your care team to better support you and monitor certain parameters that may be affected by cannabis consumption.

Conclusion

In conclusion, the legalization of cannabis means better control over the quality of the product, as well as access limited to people aged 21 and over. However, it should not be forgotten that cannabis remains a drug that presents significant health risks. Further studies will be needed to confirm the potential effects of cannabis.

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Adapted from: Ginette Lévesque (Winter 2018-2019). Cannabis and its effects on diabetes. Plein Soleil, Diabète Québec, p.26.

Updated: March 2020


Sources :

Government of Canada – Cannabis laws and regulations https://www.canada.ca/fr/sante-canada/services/drogues-medicaments/cannabis/lois-reglementation.html

Institut national de santé publique du Québec – Dossier sur le cannabis et portrait de la consommation – 2015 (9 fiches) : https://www.inspq.qc.ca/dossiers/cannabis/cannabis-effets-psychoactifs

Government of Canada – Health effects of cannabis. https://www.canada.ca/fr/sante-canada/services/drogues-medicaments/cannabis/effets-sante/effets.html

Government of Quebec – Understanding drugs and their effects. https://www.quebec.ca/sante/conseils-et-prevention/alcooldrogues-jeu/connaitre-les-drogues-et-leurs-effets/liste-des-drogues-et-de-leurs-effets/cannabis/#c5155

Government of Quebec – Health risks of cannabis use. https://encadrementcannabis.gouv.qc.ca/lecannabis/consequences-negatives-possibles-sur-la-sante-de-la-consommation-reguliere-de-cannabis/

Health Canada – Information for health professionals. Cannabis (marihuana, marijuana) and cannabinoids http://www.veterans.gc.ca/pdf/services/health/cannabis-medical-purposes/information-for-health-professionals_f.pdf

Ministère de la santé et des services sociaux (2015): Algorithm for the management of neuropathic pain. http://publications.msss.gouv.qc.ca/msss/fichiers/2014/14-947-04W.pdf

Éduc’alcool – Alcohol and mixes http://educalcool.qc.ca/wp-content/uploads/2013/08/Alcool_et_Sante_7.pdf

Studies cited:

Penner E.A, et al. The impact of marijuana use on glucose, insulin, and insulin resistance among US adults. Am J Med. 2013; 126(7):583-589 (https://www.amjmed.com/article/S0002-9343(13)00200-3/pdf)

Wallace MS, et al. Efficacy of inhaled cannabis on painful diabetic neuropathy. J Pain. 2015; 16(7): 616-627 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5152762/)

Bajaj, H. S., Barnes, T., Nagpal, S., Tricco, A. C., Rios, P., Porr, C., . . . Huot, C. (2019). Diabetes Canada Position Statement on Recreational Cannabis Use in Adults and Adolescents With Type 1 and Type 2 Diabetes. Can J Diabetes, 43(6), 372-376. doi:10.1016/j.jcjd.2019.05.010