Cannabis is a commonly used drug in Canada and is used recreationally or for its therapeutic effects.

In 2017, 4.4 million (15 percent) of Canadians reported having used cannabis in the past year. Of that population, 37 percent (or 1.6 million) said they used cannabis for medical reasons.

Medical cannabis has been legal in Canada since 2001. The federal government regulates its supply and distribution.

There is evidence that cannabis helps to relieve nausea and certain types of pain. However, more research is required to determine the therapeutic benefits of cannabis and its potential to treat other conditions.

Some people use cannabis because of the psychoactive effects produced by the chemical substance THC.

People can experience cannabis differently due to a range of factors.

Some people may feel happy or relaxed after using cannabis, while others may feel anxious, tense, fearful, and confused. Some factors that may influence how you experience cannabis include:

• how much you use
• how often and how long you’ve used it
• whether you smoke, vape, or eat it
• your mood, your expectations, and the environment you’re in
• your age
• whether you have certain pre-existing medical or psychiatric conditions
• whether you’ve taken any alcohol or other drugs (illegal, prescription, over-the-counter, or herbal).¹

Cannabis may be consumed in a variety of ways, including smoking, vaping, dabbing, or ingesting (eating/drinking).

Around 1 in 10 people who use cannabis will develop an addiction to it. This rate rises to 1 in 6 for people who start using cannabis in their teens.²

Regular use can lead to psychological dependence, including a preoccupation with using cannabis, and feelings of anxiety when it is unavailable. According to the Centre for Addiction and Mental Health, long periods of cannabis use may also result in mild physical withdrawal symptoms when a person stops using. Symptoms may last for up to a week and include irritability, anxiety, upset stomach, loss of appetite, sweating, and disturbed sleep.

Whether or not someone will develop a Cannabis Use Disorder is unique to the individual. While research in this area is still ongoing, the likelihood of developing a problematic relationship with cannabis is influenced by your length and intensity of use, the potency of the products used, your genetics and personal history, and your age of first use.³

Like alcohol and tobacco, cannabis use has health risks. These risks increase based on how long and how often you use cannabis, the potency of the product, your method of consumption (e.g. smoke, vape, eat), your family history, and your age.

Some people are more vulnerable to the potential harms of cannabis. These groups include children and youth under the age of 25, a fetus or nursing child, and those with a family history of psychosis.³

Heavy or regular cannabis is also associated with several adverse health outcomes, including:

• problems with thinking, memory, or physical co-ordination
• impairment, which can lead to serious injuries, including those from car accidents
• hallucinations, such as seeing, hearing, tasting, smelling, or feeling things that do not really exist
• mental health problems, specifically if you or an immediate family member has had a mental health issue, like psychosis or an addiction to alcohol or other drugs
• cannabis dependence
• breathing or lung problems from smoking
• cancer from smoking
• problems during or after pregnancy, especially if cannabis is smoked⁴

If you use cannabis, it is important to be aware of these risks and how you can reduce or avoid them. For more information on limiting these risks, Canada’s Lower-Risk Cannabis Use Guidelines may be helpful.

If you choose to use cannabis, Canada’s Lower-Risk Cannabis Use Guidelines outline 10 recommendations aimed at limiting possible harms associated with use:

1. Cannabis use has health risks best avoided by abstaining
2. Delay taking up cannabis use until later in life
3. Identify and choose lower-risk cannabis products
4. Don’t use synthetic cannabinoids
5. Avoid smoking burnt cannabis—choose safer ways of using
6. If you smoke cannabis, avoid harmful smoking practices
7. Limit and reduce how often you use cannabis
8. Don’t use and drive, or operate other machinery
9. Avoid cannabis use altogether if you are at risk for mental health problems or are pregnant
10. Avoid combining the risks identified above

Young people are particularly vulnerable to the risks associated with cannabis use because brain development isn’t complete until people reach their mid-20s.

Research in this area is ongoing, but it is generally accepted that adolescents who begin using cannabis before the age of 16 are at an increased risk of adverse physical and mental health outcomes.

Though it isn’t possible to predict who will experience harms from cannabis, the association between cannabis use at a younger age and several negative outcomes has led to the recommendation to delay taking up cannabis use until later in life.

For more information about the risks associated with cannabis use for young people see the Canadian Centre on Substance Abuse summary report on The Effects of Cannabis Use during Adolescence.

Cannabis use during pregnancy may affect pre-natal growth and development. Though more research in this area is needed, cannabis use during pregnancy and breastfeeding may be associated with increased risk of the following outcomes:

• Low birth weight
• Pre-term labour
• Long-term health problems (cardiovascular and mental health)
• Short and long-term learning, development, and behavioural issues

It isn’t possible to predict with certainty which individuals will experience harms from cannabis, but risks associated with cannabis use during pregnancy and breastfeeding has led to the recommendation to avoid using cannabis use if you are pregnant or breastfeeding.

For more information about cannabis use during pregnancy and breastfeeding visit the Society of Obstetricians and Gynaecologists of Canada’s Pregnancy Info webpage.

Like alcohol, using cannabis inhibits your ability to drive safely. Even at low doses, using cannabis impairs a number of cognitive functions that affect your ability to operate a motorized vehicle or heavy machinery safely. In particular, cannabis affects perception, short-term memory, decision-making, and motor skills.

The Canadian Centre on Substance Use and Addiction has compiled a summary of evidence about Cannabis Use and Driving and has identified the following highlights:

• After alcohol, cannabis is the most commonly detected substance among drivers who die in traffic crashes.
• Driving under the influence of cannabis doubles the risk of being involved in a crash.
• This risk increases even more when cannabis is used with alcohol. When used together, the effects of either drug may be more powerful, resulting in greater impairment than had either of the drugs been used alone.

Due to the association between cannabis use and the harms around drug-impaired driving, it is recommended that people don’t drive or operate machinery within 6 hours of using cannabis.

The following restrictions apply to purchasing, possessing and consuming non-medical cannabis in Ontario:

• 19 years or older is the legal age to buy, use, or possess cannabis.
• There are serious penalties for drug-impaired driving and a zero tolerance limit for young, novice, or commercial drivers.
• Adults of legal age will be permitted to possess up to 30 grams of dried cannabis in public.
• As of October 17, 2018, the Ontario Cannabis Store website is the only legal option for purchasing recreational cannabis.
• A limit of four cannabis plants may be grown per residence.
• Use of recreational cannabis is prohibited in workplaces.

The Ontario Cannabis Store (OCS) website and authorized retail stores are the only legal option for purchasing non-medical cannabis in Ontario.  Individuals must be 19 years old and present proof of age upon product delivery, or at the time of purchase if purchasing from a physical storefront.

Recreational and medical cannabis can be smoked or vaped in the following areas:

• Private residences (not including private residences that are workplaces)
• Many outdoor public places, such as sidewalks and parks
• Designated guest rooms in hotels, motels and inns
• Controlled areas in residential care facilities, psychiatric facilities, veterans’ facilities and residential hospices
• Residential boats and vehicles with permanent sleeping accommodations and cooking facilities when parked or anchored and they meet other criteria

Recreational and medical cannabis cannot be smoked or vaped in:

• Enclosed public spaces, enclosed workplaces and other sheltered areas with a roof and more than two walls (such as bus shelters)
• Vehicles and boats being driven or under someone’s care or control
• Indoor common areas of condominiums, apartment buildings and university/college residences
• Schools and school grounds, outdoor grounds of a community recreational facility and public areas within 20 metres of perimeter of those grounds
• Restaurant and bar patios, and public areas within 9 metres of a patio
• Child care centres, and places where an early years program or services is provided
• Places where home child care is provided, regardless of whether children are present
• Children’s playgrounds and public areas within 20 metres of playgrounds
• Publicly owned sporting areas (not including golf courses), adjacent spectator areas and public areas within 20 metres of these areas
• Restaurant and bar patios and public areas within 9 metres of a patio
• Nine metres from the entrance or exit of a public hospital, private hospital, psychiatric facility, long-term care home and independent health facility
• Outdoor ground of public hospitals, private hospitals, psychiatric facilities and specified Ontario buildings
• Reserved seating areas of outdoor sports or entertainment venues⁵

Municipalities have the power to enact by-laws that further restrict the consumption of cannabis in defined areas, such as parks.

At the present time, the Peterborough Smoking By-law only applies to the smoking of medical cannabis and tobacco.

Drug-impaired driving remains a criminal offence in Canada. In April 2017, the federal government introduced legislation under Bill-C36 to strengthen Canada’s impaired driving laws.

The new law gives police the authority to require a driver suspected of drug use to provide a sample of oral fluid to test for the presence of drugs, similar to the current approach for alcohol screening at roadside using approved devices. The legislation also establishes blood concentration limits for THC.