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Opioid Addiction Centre for Addiction
and Mental Health

 Health Info A-Z


Opioid Addiction

What is opioid addiction?

Opioids are a class of powerful drugs that are primarily prescribed to treat severe pain. If opioids are abused, they can create feelings of intense pleasure or euphoria, and can also lead to fatal overdose, along with other medical, legal and social problems. Opioids include illicit drugs, such as heroin, as well as prescription medications, such as Percocet, morphine and codeine. Opioids are an effective medication when used as prescribed, but they carry a risk of addiction because of their powerful effects.

Opioid addiction refers to a group of signs or symptoms and behaviours that indicate a person is both physically and psychologically dependent on the substance. Typically the person will continue to use opioids despite the fact that the drug use is causing significant physical, personal or social problems. Because tolerance develops quickly to the euphoric effects of the drug, the person will take increasing amounts of the drug in order to feel high. Through chronic exposure to the drug, the person will also show signs of physical dependence. That is, if the person abruptly stops using the drug, he or she will experience very unpleasant withdrawal symptoms, such as strong cravings, sweating, muscle aches and insomnia. Withdrawal symptoms happen when the body cannot re-adapt quickly enough to the absence of the drug.

Opioid addiction involves more than just physical dependence. For example, a person with cancer who is prescribed opioids for severe pain may experience withdrawal symptoms when he or she stops taking the medication, but is not addicted. In addition to physical dependence, opioid addiction also involves psychological dependence. This means that the drug is so central to the person’s life that the need to keep using becomes a craving or compulsion, even if the person knows continued use is harmful.

Cravings and increasing tolerance may lead the person to buy drugs on “the street” or go to more than one doctor to get the same drug. He or she may smoke, snort, crush or inject the drug in order to feel high faster and more intensely.

What are the signs & symptoms of opioid addiction?

  • needing to take more of the drug to get the same effect
  • persistently wanting to quit, or trying unsuccessfully to quit
  • spending a lot of time and effort to obtain, use and recover from opioids
  • continuing to use opioids despite negative consequences
  • crushing, snorting, smoking or injecting opioids
  • running out of prescription medications early
  • accessing two or more physicians for prescriptions
  • escalating use
  • buying opioids on the street
  • showing signs of opioid intoxication (e.g., nodding off, pinpoint pupils)
  • feeling ill (withdrawal) when the use of opioids suddenly stops
  • experiencing cravings to use
  • making the use of drugs a priority over family, work and other important obligations.

What are the causes & risk factors of opioid addiction?

Opioid addiction is caused by a combination of physical and psychological factors. They include:

  • access to opioid drugs, whether from licit or illicit sources
  • development of physical tolerance to the drug
  • use of increasing quantities of the drug
  • compulsive use
  • presence of withdrawal symptoms.

Risk factors for developing opioid addiction include:

  • personal history of substance use issues involving any substance, including alcohol
  • family history of substance use problems or addiction
  • history of preadolescent sexual abuse
  • history of psychiatric problems.

What is the treatment for opioid addiction?

Two main treatment options are available for opioid addiction:

  • substitution drug therapies using methadone or buprenorphine
  • addiction treatment counselling (e.g., withdrawal management, day treatment, mutual aid groups such as Narcotics Anonymous).

Treatment usually involves a combination of these two approaches. With opioid substitution treatment, medically prescribed methadone or buprenorphine replaces the opioid the person is addicted to. It helps the person deal with cravings and withdrawal symptoms without becoming high or otherwise impaired.

The medical goal is for the person to feel physically normal, rather than either high or craving opioids. If that goal is achieved, the person can then receive other necessary treatments (e.g., medical, psychiatric), work or attend school and address other issues (e.g., family issues or problems with other substances).

Where can I find help, treatment and support for opioid addiction?

Treatment and support are available for people living with drug use problems and addictions:

Treatment from CAMH

Help for Families from CAMH

Ontario Drug and Alcohol Helpline​ (open 24/7 for treatment anywhere in Ontario)

Kids Help Phone at 1 800 668-6868

Where can I find more resources from CAMH related to opiod addiction?

Do You Know... Opioids

Best Advice for people taking opioid medication by Dr. Mike Evans (video)


CAMH Switchboard 416-535-8501
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