Talking to Patients About Recreational Cannabis

With the upcoming legalization of recreational cannabis, you may find that more patients want to talk to you about its use. This can be approached similar to conversations about other controlled substances, like alcohol and tobacco.

This resource provides information about some health risks associated with recreational cannabis use and considerations to guide a conversation with patients about recreational cannabis.

Ontario’s doctors believe that recreational cannabis is an inherently harmful substance and the health risks caused by recreational cannabis can best be avoided by abstaining from use. There is strong evidence that demonstrates that recreational cannabis impacts brain development through early adulthood. For that reason, Ontario’s doctors advocate that those under 25 years of age abstain from recreational cannabis. More research on cannabis is required to inform broader clinical evidence.

It is important to keep in mind that this resource is intended for discussions about recreational cannabis. This document is not intended to inform discussions about medicinal cannabis used for therapeutic purposes. Further, health impacts from recreational cannabis use can vary depending on a number of factors including, but not limited to: age of user, THC levels, consumption method and frequency of use.

Cannabis 101

What is cannabis?

Cannabis is a product derived from the Cannabis sativa plant. Cannabis contains hundreds of chemical substances known as cannabinoids. Cannabinoid receptors and the endocannabinoid system process cannabinoids. Terpenes give cannabis its distinct smell.

What is the endocannabinoid system?

The endocannabinoid system is a lipid signaling system found in all vertebrates. This system has important regulatory functions throughout the body and has been linked with the following physiological and pathophysiological processes: neural development, immune function, inflammation, appetite, metabolism and energy homeostasis, cardiovascular function, digestion, bone development and bone density, synaptic plasticity and learning, pain, reproduction, psychiatric disease, psychomotor behaviour, memory, wake/sleep cycles, and the regulation of stress and emotions.

What is THC?

Delta-9-tetrahydrocannabinol (THC) is the cannabinoid responsible for how the body reacts to cannabis, including intoxication. The concentration of THC is usually shown as a percentage of THC by weight of the cannabis product or by volume if dealing with a cannabis oil. If a cannabis product has less than 0.3% of THC in its flowers or leaves it is considered as hemp.

What is CBD?

Cannabidiol (CBD) is a cannabinoid that does not intoxicate users or produce a high, but it does affect ion channels, receptors and enzymes. There is some evidence that CBD can block or decrease the effects of THC. Common effects of CBD use include: anti-inflammatory, analgesic, anti-nausea, anti-emetic, anti-psychotic, anti-ischemic, anxiolytic, and anti-epileptiform.

Other names for cannabis

Commonly used terms include ‘recreational cannabis’ and ‘adult use cannabis’ for cannabis that is used outside of a therapeutic setting. There are several other terms for cannabis. Language and terminology may vary depending on social groups, age, culture and communities.

The Government of Canada lists the following as additional names for cannabis:

• Marijuana • Skunk • Honeycomb • Mary Jane (MJ) • Pot • Shatter • Trees • Purp • Bud • Budder • Gangster • Dank or dank krippy • Dope • Errl • Keef • Weed • Wax • Rosin • Boom • Herb • Ganja

Health Effects of Recreational Cannabis

Addiction and Problematic Use

  • Recreational cannabis can be addictive. The addiction risk is 1 in 6 for those who start using as a teen.
  • Cannabis use disorder:
    • The DSM-5 defines as “a problematic pattern of cannabis use leading to clinically significant impairment or distress”.
    • Symptoms include tolerance and withdrawl.
    • Cannabis withdrawal includes: irritability, anger or aggression, anxiety, depressed mood, restlessness, difficulty sleeping, decreased appetite, and weight loss.
    • Adolescence is the most common time for onset.

Cannabis smoke & second-hand smoke

  • Exposure to cannabis smoke can trigger acute and chronic health issues that include: cardiovascular events, asthma, cancers, chronic obstructive pulmonary disease, and a range of respiratory and circulatory conditions.
  • Cannabis smokers tend to inhale more deeply and hold their breath for longer, this can push cancercausing agents to travel further into the lungs.
  • Exposure to second hand cannabis smoke contains many of the same toxins found in cannabis smoke that is directly inhaled, including carcinogens.

Cannabis and mental health

  • Recreational cannabis use can trigger or heighten symptoms of anxiety and or depression.
  • Recreational cannabis use in teenage years is linked to the development of mood and anxiety disorders and an increased likelihood of developing psychiatric disorders later in life.
  • Cannabis use and schizophrenia:
    • Increases the risk of developing schizophrenia in youth
    • Increases the risk of triggering an early onset of schizophrenia for an individual that has a genetic predisposition (for example, family history)
    • Continued cannabis use for an individual with schizophrenia can heighten psychotic symptoms

Cognitive effects

The immediate effects normally lessen within about six hours of use, although cognitive impacts have been seen for up to 3 weeks after cessation.

More evidence-based research on the cognitive impacts of cannabis is required. Below is a list of known acute and long-term effects that can be caused by cannabis use. While these effects are general, the severity may be impacted by THC levels, age of the person using, and frequency of use.



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