Opioid addiction is defined by a group of signs, symptoms and behaviours that indicate a person is both physically and psychologically dependent on the substance. These include:

• using over a longer period or using more than planned
• wanting to quit or cut down, or trying unsuccessfully to quit
• spending a lot of time and effort getting, using and recovering from opioids
• experiencing cravings
• failing to fulfil responsibilities at work, school or home as a result of opioid use
• continuing to use opioids despite the negative social consequences caused by opioid use
• giving up activities that were once enjoyable
• using opioids in dangerous situations
• needing to take more of the drug to get the same effect (tolerance, a sign of physical dependence)
• feeling ill when opioid use suddenly stops (withdrawal, a sign of physical dependence)
• crushing, snorting, smoking or injecting opioids
• running out of prescription medications early
• drawing on many sources for opioids (e.g., prescriptions from two or more physicians or both a prescription and street opioids)
• showing signs of opioid intoxication (e.g., nodding off, pinpoint pupils).

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 they stop taking the medication, but is not addicted. 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 that using 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. They may smoke, snort, crush or inject the drug in order to feel high faster and more intensely. This could affect their relationships with family members or friends, or cause a person to neglect their responsibilities.