The Difference Between Opioid Addiction and Dependence

Opioids include prescribed pain medications as well as illegal substances such as heroin. Prescribed opioids can be helpful in managing chronic pain or treating other medical conditions, but the continued use of these drugs over time can lead to opioid addiction and dependence.

What Are Opioids?

Opioids are a class of drugs that include prescription medications such as oxycodone, hydrocodone, codeine, morphine, fentanyl, and methadone.1 Heroin is also an opioid drug that is illegal.

Opioids work by binding to opioid receptors in your brain and releasing dopamine. Some effects of opioids are:1

  • Pain relief
  • Cough suppressant
  • Euphoric feeling
  • Relaxation
  • A “rush” or a “high”

Medical professionals often prescribe opioids for pain management in patients and sometimes to relieve cough or diarrhea.

Heroin is a street drug that interacts with your brain in a similar way as prescribed opioids. Heroin enters your brain quickly, especially if it is injected or snorted—two common methods of administration. Due to the synthetic nature of heroin, the potency of street drugs, and the ways it is typically used, heroin produces a more intense high than prescription opioids.

How Common Is Opioid Addiction?

The prevalence of opioid addiction has increased in recent years and is even referred to as an epidemic in America. A recent study found that in 2019:2

  • 10.1 million people misused opioids
  • 1.6 million people were found to have an opioid addiction
  • There were 48,000 deaths from an overdose of synthetic opioids
  • Over 14,000 people died from heroin overdose

Statistics show that some of these numbers increased from the previous year. From 2018 to 2019, deaths from opioids increased by more than 6% and deaths from synthetic opioids increased by more than 15%.3

One of the reasons researchers believe numbers have increased is due to an increase in prescriptions for opioids. Prescriptions for opioids like hydrocodone and oxycodone increased from 76 million in 1991 to almost 207 million in 2013.4

What Are Opioid Addiction and Dependence?

Opioids are highly addictive drugs. Opioids impact the reward center of your brain by releasing dopamine, which makes you feel good. Using opioids when you are not in pain produces euphoria that can encourage continued misuse. Misuse includes taking:1

  • Prescribed medication more often than recommended
  • A larger dose of the medicine than is prescribed
  • An opioid that was not prescribed for you, even if you take it to relieve pain
  • The medicine to feel the “high”
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If you continue to use opioids, whether prescribed or illegally, you will eventually develop a tolerance to the drug. Tolerance is when you no longer respond to the drug in the same way you did at first use which leads you to take higher doses to feel the desired effect.

Tolerance occurs because the opioid drug is hindering your brain’s natural opioid system and causing it to become less responsive.4

Psychological Dependence

Dependence is different from tolerance and addiction. When you take any medication, you run the risk of becoming dependent on it. This means your body begins to rely on the drug to function, and without it, you will experience withdrawal symptoms.

This is true for your psychological functioning as well. If your brain starts to rely on opioid drugs to feel relaxed or less anxious, you have become psychologically dependent on the drug. Some of the psychological withdrawal symptoms that you experience when you stop taking opioids are:5

  • Feeling anxious
  • Getting easily agitated
  • Having trouble relaxing
  • Experiencing sleep problems

Physical Dependence

Your body also becomes physically dependent on drugs. In the case of opioids, your brain may stop producing natural opiates since it has come to rely on the drug instead. This means your body is no longer able to reduce feelings of pain naturally. If you suddenly stop taking the drug, your body will have reactions such as:5

  • Aching muscles
  • Runny nose
  • Excessive yawning
  • Sweating and/or chills
  • Nausea, vomiting, or diarrhea

You can become dependent on a prescription opioid even if you are taking the drug as recommended by your doctor. This is why  medical professionals will slowly taper your dosage down over a period of time to avoid withdrawal symptoms.


Opioid addiction occurs when you begin to crave the effects of the drug and develop a compulsive need to continue taking the drug even when it is causing distress in your health and relationships.

How Do You Become Addicted to Opioids?

Anyone can become addicted to a substance. If you are prescribed opioids, use them recreationally, or use heroin illegally, you are at risk of becoming tolerant, addicted, or dependent on the drug.

The exact causes for why you develop an opioid addiction are not known, although research points to a combination of genetic and environmental factors.


It is believed that variations in the genes that control the opioid receptors in your brain may contribute to the development of cravings for opioid drugs. Researchers theorize that differences in the opioid receptors’ structure impact how the body responds to the release of opioids. Some factors potentially tied to genetics that raise your risk of opioid addiction are:6

  • Family history of substance misuse
  • Underlying mental health conditions such as depression or anxiety
  • Certain traits like impulsivity, risky behavior, or sensation-seeking


Research shows that your environment also contributes to opioid addiction. You are at a higher risk of becoming addicted if you:6

  • Reside in a rural area
  • Experienced childhood trauma like abuse or neglect
  • Have easy access to opioids because of social circles or place of residence
  • Live in an economically depressed area or have a lower socioeconomic status

Even if you start by taking opioids as prescribed by your doctor, addiction can occur if you misuse the medication. You may also become addicted from using the drug recreationally. The transition from prescription opioids to illegal heroin is fairly common, partially because the street drug can be cheaper and easier to get than a prescription.4

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What Are the Signs of Opioid Addiction?

There are both signs and symptoms of opioid addiction to look for in yourself or a loved one.

Some of the behavioral signs are:7

  • Changes in personality
  • Avoiding family or friends
  • Lying and secretive behavior
  • Poor performance at school or work
  • Moodiness, irritability, or nervousness
  • Stealing
  • Isolation

Some of the physical signs you may notice are:7

  • Loss of appetite or weight loss
  • Feeling tired or drowsy
  • Flu-like symptoms (muscle aches, runny nose, chills)
  • Small pupils
  • Poor hygiene
  • Sores or puncture wounds indicative of IV drug use

What Are the Treatment Options?

Treatment for opioid addiction often involves a combination of medicine, therapy, and support groups. There are three medicines the FDA has approved to treat opioid dependence; methadone, buprenorphine, and naltrexone.5

These medications are often used long-term and have proven to be effective in decreasing cravings for opioids, blocking the euphoric effects of opioids, and relieving withdrawal symptoms.

In addition to medication, treatment includes various therapeutic approaches that help you identify motivations for change and how to overcome obstacles that get in your way. You will also learn new coping strategies for stress so that you do not turn back to the drug as your coping mechanism.

If you or someone you love is addicted to opioids, please call 800-994-1867Who Answers? to speak to a specialist about your treatment options.


  1. National Institute on Drug Abuse. (2021). Prescription Opioids DrugFacts. National Institutes of Health.
  2. United States Department of Health and Human Services. (2021, October 27). About the Epidemic.
  3. Centers for Disease Control and Prevention. (2021, March 17). Understanding the Epidemic. United States Department of Health and Human Services.
  4. National Institute on Drug Abuse. (2014, May 14). America’s Addiction to Opioids: Heroin and Prescription Drug Abuse. National Institutes of Health.
  5. National Library of Medicine. (2020, May 10). Opiate and opioid withdrawal. National Institutes of Health.
  6. National Library of Medicine. (2020, August 18). Opioid addiction: MedlinePlus Genetics. National Institutes of Health.
  7. New York State Department of Health. (2017). Opioids: Recognizing the Signs.
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