Cannabis is a plant, but that doesn’t mean it is risk free. Nature is full of plants that are dangerous to humans, such as poison ivy or tobacco. Heroin and cocaine are also derived from plants. Even though the Government of Canada has legalized recreational cannabis, it does not mean it’s safe. While alcohol is legal, it has been linked to heart and liver disease. Cigarettes are legal even though they are highly addictive and can cause cancer. While some people may feel happy, relaxed or “high” after using cannabis, it can also lead to many negative health effects including:
- Anxiety and panic attacks;
- Increased risk of psychosis – a mental health disorder that can cause delusions, hallucinations and a loss of touch with reality;
- Increased risk of triggering or aggravating mood and/or psychiatric disorders such as depression, bipolar disorder or schizophrenia, particularly in those with a family history;
- Feelings of confusion, paranoia, fear or suicidal thoughts;
- Severe episodes of nausea, vomiting and abdominal pain (known as Cannabis hyperemesis);
- Loss of balance and stability, dizziness and falls;
- Serious lung diseases and respiratory infections caused by smoke containing carbon monoxide, ammonia, nitrogen oxide, hydrogen cyanide, aluminum and tar;
- Risk of chronic obstructive pulmonary disease (COPD), acute bronchitis, emphysema, pulmonary fibrosis, chronic cough and lung tumors;
- A potentially elevated risk for lung, head and neck cancer;
- Damaged blood vessels, artery inflammation, increased heart rate and chest pain, which can be dangerous for people with heart conditions and can increase the risk of heart attack or stroke;
- Severe allergic reactions such as anaphylactic shock, a life-threatening condition that can cause blood pressure to suddenly drop and airways to close;
- Mild allergic reactions such as watery eyes, runny nose, congestion, sneezing, itchiness, dermatitis, hives, nausea or vomiting;
- Problems with memory, attention, concentration, thinking, learning, making decisions and controlling emotions;
- Amotivational syndrome, which can cause lack of motivation, social withdrawal, decreased interest in activities, lethargy and impaired occupational achievement.
Contrary to popular belief, people can become addicted to cannabis. Cannabis affects the brain’s reward system in the same way that other addictive drugs do and can lead to psychological and/or physical dependence.
Studies have shown that about 1 in 11 people who use cannabis will become addicted and dependent. The risk for addiction increases to 1 in 6 if they started using as a teen. If a person smokes cannabis daily, the risk of addiction increases to 1 in 4.
Cannabis use can also lead to addiction if it is continually used to cope with emotions. While some individuals choose to use cannabis as a means to cope with depression or anxiety, cannabis use can actually worsen these conditions and stunt the emotional and coping process.
Frequent and intense use of cannabis are the two key factors that lead to long-term health problems. Youth are especially vulnerable to addiction because their brains are still developing until around the age of 25.
Cannabis Use Disorder is also recognized as a Substance-Related and Addictive Disorder in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV).
The brain does not mature until around the age of 25. Those who use cannabis while the brain is still developing are more likely to become dependent and suffer long-term health effects.
Those who begin using cannabis at a young age are more likely to develop mental health problems. Cannabis use among youth is associated with depression, anxiety and psychosis. It is also linked to impaired neurological development, which can lead to difficulties with learning, concentration, memory, attention, and school performance.
THC, the main active ingredient in cannabis, acts on targets found in the body known as cannabinoid receptors. These receptors are mostly found in the brain and central nervous system. When these receptors encounter substances found in cannabis it can affect the ability of the brain and central nervous system to function properly.
Studies have shown that people who start using cannabis at a young age have experienced functional and structural changes to their developing brain, including alterations of white and gray brain matter.
Cannabis is stronger today than it ever was before. In recent years, cannabis has become much more potent as a result of new growing and processing practices that increase the levels of THC, which can increase your health risks.
THC is one of hundreds of chemical substances known as cannabinoids. THC is the cannabinoid that is most responsible for the “high” associated with cannabis use. The average THC potency in dried cannabis has increased from about 3% in the 1980s to an average of around 15% today. Some strains of dried cannabis have THC concentrations as high as 30%.
Combining alcohol with cannabis greatly increases a person’s level of impairment, which can then increase the risk of injury or death from accidents.
Cannabis may also interact with certain prescription medications. You should avoid cannabis if you are taking any medications that slow down the central nervous system such as sleeping pills, some pain medications such as opioids, and some medications used to treat seizures or anxiety disorders, such as benzodiazepines. It should also be avoided by those taking anti-psychotic medications like clozapine or olanzapine.
Cannabis use may also result in unintended side effects if you are taking certain anti-depressants, some allergy or cold medications, stomach acid inhibitors, certain antibiotic and antifungal medications, or certain antiretroviral medications used to treat HIV/AIDS.
Smoke from cannabis contains many of the same poisons and cancer-causing toxins found in tobacco smoke. Deep, often unfiltered puffs, and breath-holding practices associated with cannabis use can lead to higher levels of carbon monoxide, ammonia, nitrogen oxide, hydrogen cyanide, aluminum and tar in the body. These chemicals damage the lungs and injure the cell linings of the large airways.
Short-term effects of smoking cannabis include airway inflammation, excessive phlegm, sore throat, wheezing, shortness of breath, and chest tightness. Severe long-term effects can include chronic cough, acute bronchitis, pulmonary fibrosis, COPD, lung tumours, and a potentially elevated risk for lung, head, and neck cancer.
Yes. Symptoms of overdose may include sleepiness, confusion, disorientation loss of coordination, dizziness, fainting, falls, as well as fast or slow heartbeat. You should seek immediate medical attention if you experience cannabis induced chest pain, panic attacks, loss of contact with reality, or seizures.
The risk of overdose becomes much higher if cannabis is combined with alcohol, certain medications (e.g. opioids or benzodiazepines), or illegal drugs.
Cannabis use during pregnancy poses a serious risk to an unborn baby. Substances found in cannabis can travel through the mother’s blood to her unborn baby during pregnancy and reduce the supply of oxygen and nutrients to the fetus, which can in turn affect brain development and lead to health problems.
Some studies have linked cannabis use to lower birth weight, slower growth and lower alertness in newborns. It can also decrease the baby’s ability to self-soothe and lead to increased sleep disturbances.
Using cannabis while pregnant also increases the risk of the child having problems with learning, memory, perception, verbal reasoning, and problem solving later in life. It can also increase a child’s risk for experiencing hyperactivity, impulsivity and attention deficits.
Substances found in cannabis, such as THC, can also pass into breast milk and become absorbed and metabolized by a baby during breastfeeding.
Cannabis use can also cause problems for couples planning a family. Men who smoke cannabis are at a higher risk of decreased sperm count, abnormal sperm, and poor motility (sperms’ ability to swim).
Driving after using cannabis doubles your risk of causing an accident. In fact, the most common cannabis related harms are fatal and non-fatal injuries from motor vehicle accidents caused by cannabis impairment.
Cannabis use impairs your concentration, alertness, reaction time, and your ability to make quick decisions or handle unexpected events. It can also make it harder to judge distances and time, and affect coordination.
There is no standard waiting time to drive after using cannabis. The Canadian Low Risk Cannabis Use Guidelines and the Canadian Public Health Association recommend not driving for at least six (6) hours or longer after consuming cannabis. Cannabis impairment may vary and last longer than six hours depending on a person’s tolerance, age, the amount of cannabis consumed, the potency of the cannabis, whether the person has pre-existing health conditions, and whether it has been used in combination with other substances.
The best way to reduce the health risks of cannabis is to avoid using it. If you do decide to use cannabis, limit how much you use and reduce how often you use it.
- Adults between the ages of 19 and 25 who intend to use cannabis should delay or limit their use to minimize the potential harm it may have on the brain.
- Avoid smoking cannabis. If you do smoke cannabis, avoid harmful smoking practices like deep puffs and breath-holding or unfiltered smoking.
- While vaporizers limit exposure to toxins found in cannabis smoke, it can still result in a high concentration of ammonia in the body and lungs, which is linked to neurological impairments.
- Educate yourself about the THC content in cannabis products and choose lower risk, low-potency cannabis products.
- If you use edible cannabis, be cognizant of the amount you consume. While the effects of smoked cannabis can reach its full effect within 15-30 minutes, edible cannabis can take 2-3 hours to reach its full effect. You can reduce your risk of edible-related overdose and hospitalization by consuming edibles slowly and cautiously.
- Edible cannabis should be kept out of the reach of children to prevent unintentional poisoning and hospitalization.
- Do not use illegal cannabis as it can be contaminated with pesticides and harmful chemicals. Illegal cannabis can also be laced with other substances like cocaine or fentanyl, which can pose serious risk to life.
NOTE: Edibles will not be available on October 17, 2018. The Government of Canada will enact regulations related to edible cannabis within a year following cannabis legalization.
- Are under the legal age to purchase and consume cannabis;
- Are pregnant, planning to become pregnant, or breastfeeding;
- Are in the presence of children;
- Are exposing others to unwanted second-hand smoke;
- Have serious liver disease, renal disease, kidney disease or heart disease;
- Have chronic obstructive pulmonary disease (COPD), asthma, emphysema or any lung disease;
- Have a family history of schizophrenia or psychosis;
- Have depression, anxiety or bipolar disorder;
- Are allergic to any cannabinoid or to smoke;
- Have chronic hepatitis C;
- Are taking fentanyl (or related opioids) or anti-psychotic medications (e.g. clozapine or olanzapine);
- Feel a loss of control over your cannabis use and a compulsion to use it continually;
- Have a substance use disorder or history of addiction; or,
- Are performing any activity that requires concentration, the ability to make quick decisions, coordination or motor skills (e.g. driving).
The medical cannabis stream remains in effect following the legalization of recreational cannabis. However, physicians do not recommend that patients access cannabis through recreational dispensaries for the purpose of self-medicating.
As with any therapy, it should be undertaken under the guidance and advice of a physician or other prescriber. All medications, particularly controlled substances such as opioids, sedative hypnotic medications and medical cannabis should be instituted first as a trial with frequent monitoring and follow up by the prescriber. Dosing, route of administration and frequency of use should be dictated by the attending physician based on the patient’s presenting illness other co-existing illnesses. Furthermore, one must always consider other medications that the patient may be taking so that potential medication interactions and potential side effects can be considered when tailoring the trial of a new therapy.
If a patient self-medicates and the medication trial is not monitored by a physician or other prescriber it places the patient at a higher risk for adverse outcomes such as overdose, medication overuse and medication misuse.
The Newfoundland and Labrador Medical Association (NLMA) has not taken a position on the Government of Canada’s decision to legalize cannabis for recreational purposes. We believe that provincial governments must use the lessons learned from alcohol and tobacco to ensure that legislation and regulations are developed to minimize the harms associated with cannabis use. While provinces may benefit from increased revenue as a result of cannabis production and sale, we believe that governments’ first priority must always be protecting the health and well-being of their citizens. This includes expanded support for prevention, early identification and cannabis cessation treatments within the framework of mental health and addictions. Governments also have an obligation to establish harm reduction strategies and to increase public awareness about the significant harms associated with cannabis use.
The Newfoundland and Labrador Medical Association (NLMA) supports the position of the Canadian Medical Association (CMA) that there is insufficient scientific evidence regarding the use, benefits and risks of cannabis for clinical purposes.
While the NLMA recognizes that some individuals suffering from terminal illness or chronic disease may obtain relief with cannabis, the NLMA remains concerned about the lack of clinical research, guidance, and regulatory oversight for cannabis as a potential medical intervention. Physicians have a lot of information on prescription drugs based on research and clinical trials. They know how much to prescribe and ho often, what the benefits are, potential interactions with other drugs and what the side effects could be. This information is limited for cannabis.
Therefore, the CMA, and by extension the NLMA, have both recommended that physicians not prescribe marijuana for medical purposes due to the failure of governments and manufacturers to provide adequate information regarding quality, effectiveness and safety.
The NLMA accepts that physicians who feel qualified to recommend medical marijuana to their patients, are able to do so in accordance with Health Canada’s regulations.
Under the federal Access to Cannabis for Medical Purposes Regulations, Canadians who have been authorized by their health care practitioner to access cannabis for medical purposes are able to grow a limited amount of cannabis for their own medical purposes, designate someone to grow it for them, or purchase it from a producer licensed by Health Canada.
Despite this, Health Canada states on its website that “Cannabis (marijuana, marihuana) is not an approved therapeutic substance in Canada and has not been issued a notice of compliance by Health Canada authorizing sale in Canada.”
One of the reasons why the Government of Canada continues to permit physicians to authorize cannabis for medical use is because they are constrained by the decisions of Canadian courts. Federal courts have consistently sided with patients’ rights to relieve symptoms of terminal disease or certain chronic conditions, despite the limited data on the drug. As such, Health Canada has issued a disclaimer to physicians that the information on its website “should not be construed as expressing conclusions from Health Canada about the appropriate use of marihuana for medical purposes.”
According to the Food and Drugs Act (FDA), all drugs requiring a health professional’s authorization must be approved for use by Health Canada based on evidence of effectiveness obtained from controlled clinical trials. Studies supporting the safety and usefulness of cannabis for medical purposes are limited and do not meet the standard required by the Food and Drug Regulations for marketed drugs in Canada. In addition, Health Canada has a system of post-market surveillance to keep track of problems that arise with prescription drugs. However, because of its unique legal position, Health Canada has exempted cannabis from the applications of the Act and its regulations.
For these reasons, medical organizations across Canada have been calling on Health Canada to require the same research and clinical trials on cannabis that is required for any other therapeutic substance in Canada.
The College of Physicians and Surgeons of Newfoundland and Labrador has issued an interim guideline to physicians outlining conditions that must be met before a physician considers completing the medical document.
NOTE: The NLMA has no data on the frequency of requests for cannabis for medical purposes, how many practitioners prescribe it or who they are.
This is a complicated question. We know that dismantling the medical cannabis system may impact some patients’ ability to access it, and that some forms of the drug (e.g. those that are modified for pediatric use in order to reduce the effects of smoke and THC) may not be available in the recreational market. At the same time, we believe that cannabis needs to be subject to the same clinical research required for any medication, which is what the medical community, continues to call for. Thus, if Health Canada is going to authorize cannabis for medical use, then it must require the same research and clinical trials that are needed before any drug can be approved as a therapeutic substance in Canada.
- Canadian Medical Association
- Government of Canada
- Health Canada
- Centre for Addiction and Mental Health
- Canada’s Lower Risk Cannabis Use Guidelines
- Canadian Centre on Substance Abuse
- College of Family Physicians of Canada
- Drug Free Kids Canada
- Canadian Medical Protective Association