What is substance use?

Many people will use substances (e.g. caffeine, prescription medication, alcohol, etc.) over the course of their lifetime without any problems. Substance use becomes a problem when it starts to have harmful effects on a person’s life (e.g. difficulties at school or at home, negative impacts on mental and/or physical health, etc.).

All substances can affect the body and the brain, both in the moment and in the long term. Some substances have higher risks and more dangerous impacts than others. It’s important to know all the facts about a substance — including the risks — before you use it.

Here are some examples of substances people may use:

  • tobacco and nicotine (in things like cigarettes, e-cigarettes, hookah, etc.)
  • alcohol
  • cannabis (also known as marijuana, weed or pot)
  • stimulants (e.g. cocaine, meth, etc.)
  • opiates (e.g. heroin, oxys, etc.)
  • sedatives (e.g. prescription drugs such as Ativan, Valium, Xanax, etc.)
  • hallucinogens (e.g. LSD, magic mushrooms, etc.)
  • inhalents (e.g. glue, gasoline, etc.)

Why do people use substances?

People use substances for a variety of reasons. Some may use substances out of curiosity, or because they’re influenced by their friends, family and/or peers.

All substances have mood-altering effects, and some can stimulate the brain to “feel good” — at least temporarily. Some people use substances to cope with difficult feelings (e.g. sadness, anxiety, anger, etc.) or when stress becomes more than they know how to handle.

Young people’s brains are still developing into their twenties, which means the “judgment” part of the brain is still growing. A young person’s brain can have difficulty knowing how much is “too much,” knowing when to stop and fully understanding all the risks of long-term substance use (e.g. impacts to internal organs, brain function, attention span, memory, etc.).

If a person uses a substance often, it can cause chemical changes in their brain and body, which can make it difficult to stop using. For example, many drugs make people “feel good” because they encourage the brain to overproduce a naturally occurring chemical called dopamine. Eating, exercising, meditating and listening to music are some activities that produce dopamine. When dopamine is released, a person may experience feelings of euphoria, happiness and pleasure. When a person’s dopamine level drops (e.g. when they stop using the drug, when their body learns to tolerate the drug, etc.) they may not have those same good feelings, partly because their brain has lost some of its ability to produce dopamine naturally. This means they may want to continue using the drug in order to experience those good feelings again, and/or to mask any not-so-good feelings (e.g. sadness, anxiety, anger, etc.) they may be dealing with.

Struggling with substance use can be difficult, and completely stopping use is not easy. Withdrawal refers to the physical and emotional symptoms that a person experiences when they drastically reduce their substance use or completely stop using substances (going “cold turkey”). Signs and symptoms of withdrawal can include anything from mild discomfort (such as a headache) to seizures. Some of the effects of withdrawal can be fatal.

When does substance use become a problem?

“Addiction” is a common term used to describe when a behaviour is out of control, usually in a harmful way. The meaning of addiction may vary by person or culture. When it comes to the risks and harms of substance use, we prefer to use the terms “problematic substance use” or “substance use problem,” which describe the use of a substance over time that causes negative effects (e.g. adverse physical, emotional and/or social impacts).

The presence of one or more of these factors can be a sign of a substance use problem:

  • craving a substance (feeling like you have to have it)
  • feeling out of control of how much or how often you use a substance
  • feeling a compulsion (urge) to use a substance
  • using a substance despite negative effects

The risks and harms of substance use can range from mild to severe. They may also vary depending on the substance. These harms may include:

  • missing school and/or work because of substance use
  • having tried cutting down or stopping unsuccessfully
  • needing a substance to have fun
  • lying about or hiding substance use from friends/family
  • not being able to just have one drink (hit, dose, etc.) or persistent “binging” (using a lot at one time)
  • building an increased tolerance to the substance; gradually needing more and more of it to get the same feeling
  • spending a lot of time planning how you will get and use the substance
  • avoiding situations or activities where no substances will be present
  • repeated behaviour while under the influence of a substance that could cause harm to you or others (e.g. illegal activity, unsafe sex, etc.)

There are factors that can help protect a young person from developing a substance use problem. They include:

  • having a positive role model or mentor, like a parent/caregiver, teacher or coach
  • having parents or other caregivers regularly available to them
  • feeling a strong sense of connection to their family, school or community
  • having goals and dreams for the future
  • participating in extracurricular activities, such as clubs, sports teams or volunteer work

What are the risks of substance use?

There are physical, emotional and social risks associated with substance use. Here are some examples:

Physical risks

  • an overdose can cause serious and sudden physical or mental damage, or even death
  • alcohol can cause liver damage
  • people who inject substances with used needles can get viral infections such as hepatitis or HIV-AIDS
  • substance use during pregnancy can harm the fetus
  • people who use illegally obtained substances can’t know for sure what they’re taking (e.g. some drugs mixed with other drugs/chemicals can be harmful, etc.)
  • driving under the influence (i.e. while drunk or high) can affect a person’s attention, reaction time and ability to judge distances, which can increase the risk of death or injury to you or others
  • some substances can affect co-ordination, the senses, memory and judgment, which can lead to safety risks (like stumbling into traffic)

Emotional risks

  • substance use can get in the way of developing and using healthier coping strategies to deal with difficult feelings (e.g. sadness, anxiety, anger, etc.)
  • substance use can sometimes make emotional difficulties worse in the long run, and can be especially harmful to young people at risk of developing mental disorders (e.g. depression, psychosis, etc.)
  • some substances can cause short-term confusion, anxiety or mental disturbances, learning problems and/or memory loss

Social risks

  • substance use may cause stress on a person’s relationships and increase the likelihood of conflict (e.g. with parents/caregivers, partners, friends, teachers, etc.)
  • substance use can interfere with a person’s ability to function at their best at school and/or work
  • because some substances are obtained illegally, substance use can be associated with violence and crime
  • substance-related convictions may result in a fine, prison sentence and criminal record. Having a criminal record may affect future convictions, jobs and travel.

If you choose to use substances, it’s important to have all the facts. If you’re concerned that you or someone you know has a substance use problem, you can search Resources Around Me for support services in your area. If you have questions about substance use, you can always call a Kids Help Phone counsellor at 1-800-668-6868.


If you would like to know more about this topic, you can connect with a counsellor by phone or Live Chat.

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