Opioid Use Disorder

Opioid Use Disorder (OUD) is a medical condition characterized by a problematic pattern of opioid use leading to clinically significant impairment or distress1. Given its potential to drastically affect the lives of those afflicted and the people around them, it is essential to understand the nuances of OUD comprehensively.

Opioid Use Disorder is a complex and multifaceted medical condition that impacts individuals on various fronts: physically, mentally, socially, and economically.

Recognizing the signs, understanding the mechanisms, and acknowledging the repercussions are essential first steps in addressing the challenges faced by those with OUD and their loved ones.

What are Opioids?

Opioids are a class of drugs that include the illegal drug heroin, synthetic opioids like fentanyl, and pain relievers available legally by prescription, such as oxycodone, hydrocodone, codeine, and morphine2.

Opioids act on the opioid receptors in the brain to produce a euphoric effect and are commonly prescribed for their effective pain-relieving properties.

Criteria for Opioid Use Disorder

The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) provides criteria to diagnose OUD3. A person must meet at least two of these criteria within a 12-month period:

  • Opioids are often taken in larger amounts or over a longer period than intended.
  • Persistent desire or unsuccessful efforts to cut down or control opioid use.
  • A lot of time is spent in activities necessary to obtain, use, or recover from the effects of opioids.
  • Craving, or a strong desire to use opioids.
  • Recurrent opioid use resulting in a failure to fulfill major role obligations at work, school, or home.
  • Continued opioid use despite having persistent or recurrent social or interpersonal problems caused or exacerbated by the effects of opioids.
  • Important social, occupational, or recreational activities are given up or reduced because of opioid use.
  • Recurrent opioid use in situations in which it is physically hazardous.
  • Continued opioid use despite knowledge of having a persistent or recurrent physical or psychological problem likely caused or exacerbated by opioids.
  • Tolerance, as defined by either of the following:
    • A need for markedly increased amounts of opioids to achieve intoxication or desired effect.
    • A markedly diminished effect with continued use of the same amount of opioids.
  • Withdrawal, manifested by either of the following:
    • The characteristic opioid withdrawal syndrome.
    • Opioids are taken to relieve or avoid withdrawal symptoms.

Mechanism of Opioid Dependence

  • Brain Chemistry: Opioids work by binding to specific receptors in the brain, spinal cord, and gastrointestinal tract. They reduce the perception of pain and can produce a sense of euphoria. However, over time and with prolonged exposure, the brain comes to rely on these drugs to maintain pleasurable feelings and avoid feelings of pain or discomfort, leading to dependence4.
  • Reward System: The brain’s reward system is activated by opioids. This system controls feelings of pleasure and reinforces behaviors that produce enjoyable outcomes. Over time, the consistent use of opioids can change the way this system works, making the consumption of opioids the primary way to achieve pleasurable feelings5.

Consequences of Opioid Use Disorder

  • Physical Health: Chronic use of opioids can lead to respiratory depression, constipation, a weakened immune system, and potential overdose6.
  • Mental Health: Opioid dependence can contribute to various mental health issues, including depression, anxiety, and other mood disorders7.
  • Social Implications: Individuals with OUD may distance themselves from family and friends, lose interest in activities, face job losses, and encounter legal problems.
  • Economic Impacts: The direct and indirect costs associated with OUD, including healthcare expenses, lost productivity, and costs related to criminal justice, are considerable8.



  1. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Arlington, VA: American Psychiatric Publishing.
  2. National Institute on Drug Abuse. (2020). Opioids. Retrieved from NIDA website.
  3. American Psychiatric Association. (2013). Opioid use disorder diagnostic criteria. In DSM-5.
  4. Kosten, T. R., & George, T. P. (2002). The neurobiology of opioid dependence: Implications for treatment. Science & Practice Perspectives, 1(1), 13–20.
  5. Koob, G. F., & Volkow, N. D. (2010). Neurocircuitry of addiction. Neuropsychopharmacology, 35(1), 217–238.
  6. White, J. M. (2004). Pleasure into pain: The consequences of long-term opioid use. Addictive Behaviors, 29(7), 1311–1324.
  7. Grattan, A., Sullivan, M. D., Saunders, K. W., Campbell, C. I., & Von Korff, M. R. (2012). Depression and prescription opioid misuse among chronic opioid therapy recipients with no history of substance abuse. The Annals of Family Medicine, 10(4), 304–311.
  8. Florence, C. S., Zhou, C., Luo, F., & Xu, L. (2016). The economic burden of prescription opioid overdose, abuse, and dependence in the United States, 2013. Medical Care, 54(10), 901.