Cannabis and Health Effects

Cannabis does not have the same effect on everyone and can lead to dependence. Cannabis can be harmful to mental and physical health.

When making decisions about using cannabis, it is important to consider the health effects. The effects of cannabis can be different for each person depending on genetics, how much cannabis is used, how it is used and what type of cannabis. It’s safest to start with low strength THC and wait for the effects before consuming more.

Health effects

While cannabis may make you feel relaxed and happy, you could experience unpleasant, unwanted or negative effects on your brain and body.  Using cannabis can have health risks for everyone, however, this risk is higher for youth, people with a family history of mental health challenges and people who are pregnant or breastfeeding.

For more information see the health effects of cannabis from Health Canada.

Types of cannabis products


Edibles refer to food or drinks that contain active cannabinoids (THC, CBD). The effects of edible cannabis take longer to feel and last longer than smoking or vaping. Learn more about using edibles responsibly.

Since there may be a delay between the time of use and the time it takes to experience effects, this can cause a person to consume more in a short amount of time, resulting in over-intoxication. Over-intoxication can include symptoms of severe anxiety and panic, nausea and vomiting, and symptoms of psychosis (paranoia).


Cannabis cream is put on the skin. Cannabis cream is usually higher in CBD and lower in THC and is generally used for medical purposes.


Cannabis extracts like hash, kief, wax, or shatter contain a high concentration of THC. High THC products (over 30%) increase the risk of experiencing mental health challenges and dependence. High THC products can change how the brain grows, affecting performance and cognitive function.


Leaves and buds from the cannabis plant can be smoked or vaped. Heating the leaves or buds activates the THC. 

Find out more about the different forms of cannabis from Health Canada.

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Cannabis use while pregnant and breastfeeding

Cannabis use in any form while pregnant and breastfeeding may have negative effects on both you and your baby. Do not use cannabis if you are trying to get pregnant, are pregnant, breastfeeding or parenting your child. If you have further questions, please contact your health care provider.

 Cannabis can affect you and your partner when you are trying to become pregnant by:
  • changing your menstrual cycle
  • lowering sperm count
  • reducing sperm quality

Cannabis crosses the placenta and your baby absorbs the chemicals that are in cannabis. Do not use cannabis while you are pregnant. If you are using cannabis for nausea, talk to your doctor about safe alternatives that are less risky to your baby’s growth and development.

Some immediate effects of cannabis use during pregnancy include:

  • low birth weight
  • pre-term birth
  • lower IQ scores
  • impulsivity and hyperactivity
  • brain development slows

Some effects of cannabis use during pregnancy that affect your child later in life include:

  • decreased ability to self soothe
  • sleep disturbances
  • poor memory
  • attention difficulties
  • hyperactivity and impulsivity
  • difficulty learning
  • depression and anxiety
  • reduced school performance
  • more likely to start using substances

Breastfeeding is the healthiest choice for your baby. Do not to use cannabis while you are breastfeeding. Cannabis passes into the breast milk and is taken into the baby’s fat cells and their brain.

Cannabis can affect your breastfed baby by:

  • slowing baby’s movements and responses
  • slowing baby’s brain development
  • baby becoming sedated

Cannabis can affect breastfeeding by:

  • lowering mother’s breast milk supply
  • baby having poor suck
  • baby becoming drowsy

Sources: Risks of Cannabis on Fertility, Pregnancy, Breastfeeding and Parenting and Women and Cannabis

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