In places where cannabis has been legalized, edibles have become more popular than the traditional ways of using cannabis because they do not affect the lungs. 1
Health effects of cannabis
Effects can be felt within seconds to minutes of smoking, vaporizing or dabbing cannabis. These effects can last up to 24 hours. If you eat or drink cannabis, these effects can occur within 30 minutes to 2 hours and can last up to 24 hours.
On this page
- Short-term health effects
- Long-term health effects
- Effects on different age groups
- Health effects during pregnancy and breastfeeding
- Potential therapeutic uses of cannabis
Short-term health effects
The flowers and leaves of the cannabis plant are used for their ability to cause effects on the mind, including:
- feeling high (euphoria)
- a sense of well-being
- relaxation
- heightened sensory experiences:
- sight
- taste
- smell
- sound
While cannabis may make you feel relaxed and happy, your body and brain may also experience effects that are:
- negative
- unwanted
- unpleasant
Some of the short-term effects on your brain can include:
- confusion
- sleepiness (fatigue)
- impaired ability to:
- remember
- concentrate
- pay attention
- react quickly
Short term effects on your body can also include:
- if smoking, damaged blood vessels caused by the smoke
- decreased blood pressure, which can cause people to faint
- increased heart rate, which can be dangerous for people with heart conditions and can lead to an increased risk of heart attack
Cannabis use can also result in psychotic episodes characterized by:
- paranoia
- delusions
- hallucinations
Long-term health effects
Long-term effects develop gradually over time, with daily or near-daily (weekly) use that continues over:
The long-term effects of cannabis on your brain can include an increased risk of addiction. Long-term cannabis use can also harm your:
- memory
- concentration
- intelligence (IQ)
- ability to think and make decisions
Effects appear to be worse if you:
- start using early in adolescence
- use frequently and over a long period of time
These effects can last from several days, to months or longer after you stop using cannabis. They may not be fully reversible even when cannabis use stops.
Other long-term effects of smoking cannabis are similar to the effects of smoking tobacco. These effects can include risks to lung health, such as:
- bronchitis
- lung infections
- chronic (long-term) cough
- increased mucus buildup in the chest
Effects on different age groups
Depending on your age, there are various factors to consider when deciding to use cannabis. Learn more about how cannabis affects:
- youth aged 13–17 years
- young adults aged 18–25 years
Health effects during pregnancy and breastfeeding
Just like with tobacco and alcohol, a pregnant woman or new mother’s use of cannabis can affect her fetus or newborn child.
The substances in cannabis are carried through the mother’s blood to her fetus during pregnancy. They are passed into the breast milk following birth. This can lead to health problems for the child.
Cannabis use during pregnancy can lead to lower birth weight of the baby. It has also been associated with longer-term developmental effects in children and adolescents, such as:
- decreases in:
- memory function
- ability to pay attention
- reasoning and problem-solving skills
Potential therapeutic uses of cannabis
There is some evidence of potential therapeutic uses for cannabis or its component chemicals (cannabinoids).
- potential therapeutic uses
- dosing
- warnings
- adverse effects
For more information
- About cannabis
- Cannabis and mental health
- Cannabis impairment and safety risk
- Driving while impaired by a drug
- Minimizing your risk when smoking, vaping and dabbing
- Thinking about using cannabis before or during pregnancy?
- Thinking about using cannabis while parenting?
- What is chronic pain
Manitoba Health
Smoking cannabis frequently over a long period of time can damage your lungs, particularly if you hold the smoke in after inhaling. Daily or near-daily use of cannabis increases the risk of developing anxiety or depression, psychosis and schizophrenia. It could also affect your ability to become pregnant by disrupting menstrual cycles or reducing sperm count. Becoming dependent on cannabis is also a risk and many people who try to quit experience withdrawal symptoms such as irritability, sleeping difficulties, cravings and anxiety.
If you choose to use cannabis, the only way to avoid these risks is to use it infrequently, taking breaks from using cannabis, using products with lower levels of THC and higher levels of CBD, and limiting the amount of cannabis that you use in a single day. For more information on reducing your risks, check out the Lower-Risk Cannabis Use Guidelines.
Effects on lungs
Smoking cannabis causes toxic by-products to be released, and inhaled, similar to those found in smoking tobacco cigarettes. Some studies show vaping reduces the toxins and carcinogens released into the lungs.
When using cannabis and tobacco together, you increase your risk of developing breathing problems. Smoking cannabis with tobacco could increase the risk of tobacco-related lung disease such as asthma, chronic obstructive pulmonary disorder (COPD) and lung cancer.
In places where cannabis has been legalized, edibles have become more popular than the traditional ways of using cannabis because they do not affect the lungs. 1
Anxiety and depression
Research has shown that teenagers with high levels of anxiety might start using cannabis at a younger age, and they may increase the amount and frequency of use more quickly than other teens. Teen girls who experience depression may also use larger amounts of cannabis more often than peers.
Frequently using cannabis to self-medicate for anxiety and depression, rather than developing healthy coping skills, can make it more difficult to recover from these problems.
There is conflicting evidence about cannabis and its effectiveness to treat anxiety. If you are using or considering trying cannabis to treat your anxiety or depression, speak to your health care provider.
Psychotic disorders
It is not recommended to use cannabis if you have a personal or family history of psychosis, schizophrenia, or bipolar disorder.
Most cannabis users will not develop schizophrenia, but for those already at risk of developing schizophrenia, either due to family history or other risk factors, cannabis can increase this risk. This is especially true if cannabis use starts when a person is young, or if a person uses cannabis frequently.
Chronic symptoms of psychosis may also appear when cannabis is used frequently or from an early age. These can persist even after cannabis use has stopped. This may not occur in every cannabis user, but using cannabis for long periods of time greatly increases a person’s risk.
For conditions like bipolar disorder, where periods of mania or psychosis may be triggered, cannabis increases the likelihood that these manic periods will occur.
Poor memory, concentration, and motivation
Frequent, long-term use of cannabis can negatively affect your memory, your ability to concentrate at school or work, and for some people will make it more difficult to become motivated. As a result, long-term cannabis use has been associated with lower grades and poorer work performance.
Addictiveness
Addiction (or dependency) to any drug is a serious and often relapsing chronic disease.Cannabis use disorder is “a problematic pattern of cannabis use leading to clinically significant impairment or distress.” 2 Dependency happens in about nine per cent of cannabis users, compared to alcoholism, which occurs in 23 per cent of users. People who have a cannabis use disorder can have a difficult time quitting or cutting back on use, or may experience withdrawal symptoms if they do. Withdrawal symptoms include anxiety, irritability, upset stomach, loss of appetite, disturbed sleep and depression. 3
Signs of cannabis use disorder include:
- craving cannabis
- not completing important responsibilities at work, school or home;
- giving up important social or occupational activities
- using cannabis more often or in larger amounts to achieve the desired effects
- having difficulty cutting down on or controlling cannabis use
