The Effects of Cannabis

Now that marijuana is legal for use by adults over age 19 in Canada, it’s important to know how marijuana may affect you, both now and in the future. The effects may be more pronounced depending on how often you use cannabis.

The effects of marijuana use can be different for everyone.

Common effects may include:

  • A happy, relaxed or “high” feeling.
  • Slower reactions and hand/eye coordination.
  • Distorted perceptions of time and distance.
  • Trouble thinking, learning and remembering.
  • Anxiety, panic or paranoia.
  • Faster heart rate.
  • Increased blood pressure.
  • Less interest in normal activities.
  • Increased appetite.
  • Dry mouth.
  • Red eyes.
  • Psychosis — seeing or hearing things that aren’t real (more common with higher doses of THC).
These effects typically last two to four hours after marijuana is smoked or inhaled. When marijuana is eaten, the effects take longer to start and may last four to 10 hours. Marijuana can vary in its potency, or strength, depending on the plant and extraction process.
 

Used too much?

The symptoms of using too much marijuana are similar to the typical effects of using marijuana, but more severe. These symptoms may include:

  • Extreme confusion, anxiety, panic or paranoia.
  • Fast heart rate.
  • Hallucinations or delusions.
  • Increased blood pressure.
  • Severe nausea and vomiting.
Increasing numbers of people are going to the emergency room after using marijuana, possibly because they used too much. This may happen because they:
  • Thought a marijuana product was regular food.
  • Used a product with more THC than they thought, either because they’re using marijuana for the first time or trying a high-THC product.
  • Consumed homemade edibles without a clear understanding of the THC content.
  • Consumed more marijuana edibles than they needed since they didn’t feel the effects right away. The effects of marijuana edibles may take up to four hours to peak after ingesting.

Overview

Driving while affected by alcohol or drugs is a leading cause of death on the roads. Every year in B.C., thousands of people operate a motor vehicle while under the influence of alcohol and / or other drugs which affect their ability to drive. This is a serious concern because the risk of motor vehicle collisions that result in injuries and / or fatalities significantly increases when the driver is affected by alcohol or drugs.Two Laws Addressing Alcohol, Drugs and Driving

Federal Law

The Criminal Code (Part VIII.1) states it is a criminal offence to operate a motor vehicle (whether in motion or not) while impaired by alcohol, a drug or a combination of alcohol and a drug.  This includes operating a motor vehicle with a Blood Alcohol Content (BAC) equal to or exceeding 80 milligrams (mg) of alcohol in 100 millilitres (mL) of blood (0.08 BAC), or operating a motor vehicle with a blood drug concentration equal to or exceeding a prescribed value. 

For more information, visit the Government of Canada’s Blood Drug Concentration Regulations.

For example, offences relating to the operation of a motor vehicle while impaired by Tetrahydrocannabinol (THC) include:

  • A summary conviction where a driver has at least 2 nanograms (ng) but less than 5 ng of THC per mL of blood within two hours of driving;
  • A hybrid offence where a driver has at least 5 ng or more of THC per mL of blood; and
  • A hybrid offence where a driver has a combined BAC of 50 mg of alcohol per 100 mL of blood (0.05 BAC), combined with a THC level equal to or exceeding 2.5 ng per mL of blood within two hours.

If police have reasonable grounds to believe a person is committing, or at any time within the preceding two hours has committed an impaired operation offence, they may request that the person provide a sample of breath or blood or may request that a person submit to an evaluation by a Drug Recognition Expert (DRE) and provide a sample of a bodily substance. It is also an offence to fail or refuse to comply with a demand.

For criminal offences to become criminal convictions, under the Criminal Code, police need to lay charges and those charges need to be prosecuted through the court system. The consequences for convicted offenders are determined by judges and can include jail time, monetary penalties, driving prohibitions and / or restrictions.

 
Research has shown that long-term use of marijuana can cause:
  • Respiratory effects:
    • Marijuana smoke irritates the lungs.
    • People who smoke marijuana daily or near-daily may have a daily cough, bronchitis, mucus and wheezing.
    • Both firsthand and secondhand smoke contain the same cancer-causing chemicals as tobacco smoke.
    • Vape products can contain nicotine, marijuana (THC or CBD), or other substances like flavoring agents or additional chemicals. While vaping products have grown in popularity, we have seen outbreaks of lung illnesses linked to vaping. The long-term health effects of vaping are unknown, and as information on the illness emerges, our best advice is to not vape at all.
  • Lung cancer:
    • There is conflicting research about smoking marijuana and lung cancer.
    • The cancer-causing chemicals in tobacco smoke are also in marijuana smoke.
    • People who smoke marijuana daily or near-daily may have tissue damage in the airways of their lungs. More research is needed to determine if this tissue damage increases the likelihood of developing lung cancer.
  • Brain and mental health effects:
    • Heavy use of marijuana can damage your memory. This damage can last a week or more after the last time you used.
    • Marijuana, especially in high doses, can cause temporary psychosis (not knowing what is real, hallucinations and paranoia) while you are high.

There’s no known safe amount of marijuana use during pregnancy or while breastfeeding.

  • Marijuana is now legal for adults over 21. But this doesn’t mean it’s safe for pregnant or breastfeeding moms or babies.
  • You shouldn’t use marijuana while you’re pregnant, just like you shouldn’t use alcohol and tobacco.

Talk to your doctor if you’re pregnant or breastfeeding and need help to stop using marijuana. Or call 1-800-CHILDREN for help.

  • Talk to your doctor if you use marijuana for medical reasons. There are other, safer choices to treat medical problems during pregnancy.

Breathing marijuana smoke is bad for you and your baby.

  • Marijuana smoke has many of the same chemicals as tobacco smoke. Some of these chemicals may cause cancer.
  • Don’t allow anyone to smoke in your home or around your baby.

Marijuana use during pregnancy

  • Using marijuana while pregnant may harm your baby.
    • Tetrahydrocannabinol (THC) is the chemical in marijuana that makes you feel “high.” Using marijuana while you’re pregnant passes THC to your baby.
    • THC may make it hard for your child to pay attention and learn, especially as your child grows older. This would make it harder for your child to do well in school.
  • THC in any form of marijuana may be bad for your baby.
    • Some people think that using a vape pen or eating marijuana (in cookies or brownies, for example) is safer than smoking marijuana. Even though these forms don’t have harmful smoke, they still contain THC.
  • There may be legal consequences for using marijuana while pregnant.
  • If you are pregnant or a mother with young children, you are a priority for drug and alcohol treatment. Treatment is available where your children are welcome. Your treatment will be confidential and nonjudgmental. Medicaid/sliding scale fees.

Marijuana use while breastfeeding

  • The Canadian Academy of Pediatrics says mothers who are breastfeeding their babies shouldn’t use marijuana.
  • Breastfeeding has many health benefits for both the baby and the mother. But THC in marijuana gets into breast milk and may affect your baby.
  • Because THC is stored in body fat, it stays in your body for a long time. A baby’s brain and body are made with a lot of fat. Since your baby’s brain and body may store THC for a long time, you shouldn’t use marijuana while you’re pregnant or breastfeeding.
  • Breast milk also contains a lot of fat. This means that “pumping and dumping” your breast milk may not work. Alcohol isn’t stored in fat, so it leaves your body faster.
Youth are at special risk for harm
  • Brain development isn’t complete until age 25. For the best chance to reach their full potential, youth shouldn’t use marijuana.
  • Youth who use marijuana regularly are more likely to have a hard time learning, problems remembering, and lower math and reading scores. These effects can last weeks after the last time they used marijuana.
  • Marijuana is addictive. It’s harder to stop using marijuana if started at a young age.
  • Youth who start using marijuana, alcohol or other drugs may be more likely to continue using later in life.

Marijuana use can, in some cases, lead to addiction. This means a person can’t control or stop marijuana use even though it interferes with daily life. Youth who begin using marijuana regularly are more likely to become addicted than those who wait until adulthood to use.

Signs of marijuana addiction
It’s important to know how to recognize when marijuana use is becoming too much.

The user may:

Be stoned or high more than one to two hours per day on a regular basis.
Not be able to stop using marijuana once he/she starts.
Be stoned often enough that he/she fails to complete big tasks or commitments.
Begin to spend a great amount of time focused on buying, using or recovering from marijuana use.

Have problems with concentration or memory loss.
Begin to take more risks while stoned, such as driving or caring for children.
Begin to talk about cutting back on his/her marijuana use.
Experience symptoms of withdrawal after not using marijuana for some time.