Relying on marijuana alone as treatment or for managing side effects while avoiding or delaying conventional medical care for cancer may have serious health consequences. 2
Edibles, or food and drink products infused with marijuana and eaten, have some different risks than smoking marijuana, including a greater risk of poisoning. Unlike smoked marijuana, edibles can:
Studies of man-made forms of the chemicals found in the marijuana plant can be helpful in treating nausea and vomiting from cancer chemotherapy. 1 Studies have found that marijuana can be helpful in treating neuropathic pain (pain caused by damaged nerves). 1
Secondhand marijuana smoke
About 1 in 10 marijuana users will become addicted. For people who begin using before the age of 18, that number rises to 1 in 6. 1-3
Other risks of regularly using cannabis can include:
The risk of developing a psychotic illness is higher in people who:
Read the latest updates on cannabis, cannabinoids and cancer – the evidence so far on the Cancer Research UK website.
Cannabis and mental health
Cannabis also increases the risk of a relapse in people who already have schizophrenia, and it can make psychotic symptoms worse.
Regularly smoking cannabis with tobacco also increases the risk of becoming addicted to nicotine and experiencing withdrawal symptoms from nicotine as well as cannabis if you cut down or give up.
It's possible to get addicted to cannabis, especially people who are considered regular or heavy users.
Clinical trials are under way to test cannabis-based drugs for other conditions including cancer pain, the eye disease glaucoma, appetite loss in people with HIV or AIDS, and epilepsy in children.
If you have questions, visit your health care provider.
Research suggests that there are ways to reduce the risks:
If you’ve consumed cannabis and are experiencing particularly unpleasant or harmful effects:
Lowering your risks when consuming cannabis
Avoid cannabis completely if you are pregnant or breastfeeding. Substances in cannabis are transferred from the mother to child and can harm your unborn or newborn baby.
Starting as a teen, consuming frequently (daily or near daily) and over a long time (several months or years) increases the risk of mental health problems. These problems include dependence and disorders related to anxiety and depression. Footnote 11
Cannabis affects the same biological system in the brain that is responsible for brain development. Footnote 11
Store all cannabis products safely, keeping them out of reach of children, youth and pets. This is particularly important for edible cannabis, which may be mistaken for regular food or drinks.