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Why Are Opioids So Addictive? 6 Questions, Answered

By Manjari Bansal
Millions of Americans misuse opioids every year. But what makes these drugs so addictive?

Opioids work by blocking out pain and making you feel calm and happy, which can lead to a potential for abuse and addiction. Once someone meets the clinical criteria for an opioid addiction, it's known as opioid use disorder, or OUD. The 2018 National Survey on Drug Use and Health reports that approximately 10 million Americans misuse opioid painkillers each year.

“Human nature is to maximize pleasure and minimize pain,” addiction counselor Lin Sternlicht, LMHC, MA, EdM, tells WebMD Connect to Care. “ Opioids are highly effective at doing so on a psychological and physiological basis.” The power of these addictive drugs lies in their ability to disrupt essential neurochemical systems in our bodies. So why are opioids so addictive? Read on for the answers to six key questions. 

1. What is the purpose of an opioid?

Opioids, also called narcotics, are a group of drugs that are prescribed by your doctor to treat moderate to severe pain, states the Cleveland Clinic. These drugs are either naturally derived from poppy plants or made synthetically in the lab. Both forms act similarly by binding to opioid receptors in your body and blocking the sensation of pain. Opioid receptors are present throughout your nervous system as well as your gastrointestinal tract and control many body functions like:

  • Pain
  • Stress
  • Mood
  • Breathing 
  • Pleasure
  • Digestive functions

When opioid drugs bind with opioid receptors, they start a series of chemical reactions that regulate the transmission of pain signals. Additionally, opioids increase the release of dopamine, sometimes called the “happiness” hormone in your body, which leads to feelings of euphoria. Euphoria–the state of intense happiness and pleasure–is the main reason why opioids are highly addictive.

Medically, opioids are approved for managing moderate to severe pain in conditions like:

  • Cancer-related pain
  • Pain after surgery
  • Few cases of acute pain
  • Vascular pain

“Pharmaceutical opioids are typically used to treat pain but can also be used to treat coughs, diarrhea, and other conditions,” Clare Waismann, M-RAS, SUDCC II, Founder and Director of Waismann Method® and Domus Retreat in California, tells WebMD Connect to Care. “They change the brain's perception of pain and are generally safe when taken for a short period and as directed.” 

According to the National Library of Medicine, commonly prescribed opioids are:

  • Morphine
  • Codeine
  • Oxycodone
  • Fentanyl
  • Buprenorphine
  • Hydrocodone
  • Methadone

“Prescription opioids are usually taken orally or injected under the skin,” Colleen Wenner, LMHC, LPC, MCAP, Founder & Clinical Director of New Heights Counseling & Consulting, tells WebMD Connect to Care. “In general, opioids are considered safe for short-term use. However, long-term use can lead to tolerance, withdrawal symptoms, and the potential development of addiction. Addiction is characterized by compulsive drug taking despite adverse consequences. Illegal street versions of prescription opioids, such as heroin, have been linked to thousands of deaths in recent years. Opioid overdose has become one of the leading causes of accidental death in the United States.” 

2. What effects do opioids have on the body?

According to the National Institute on Drug Abuse (NIDA) as well as decades of research outlined by the US Library of Medicine, opioids are known to cause the following: 

  • Stimulate endogenous opioid receptors in the nervous system
  • Reduce pain
  • Provide a feeling of relaxation
  • Bring about euphoria
  • Boost reward pathway chemicals like dopamine
  • Reinforce drug use behaviors
  • Lead users to crave more

“Over time, the individual’s body struggles to produce natural neurotransmitters as it becomes dependent on the substance to produce them,” Sternlicht says. “This is often why some individuals dependent on opioids report having a low mood when they are not under the influence of the substance or report needing the substance just to ‘feel normal.’”

A 2018 study in Borderline Personality Disorder Emotional Dysregulation found that using opioids leads to emotional irregularities, including negative thoughts and feelings, as well as a lesser capacity for experiencing pleasure without drugs. When people with chronic pain start to depend on opioids, they may begin to feel hopeless about their pain, seeing no way out except for drug use.

“Opioids become so addictive because they give the user a break from their own mind. Aside from the physical relaxation of the body, and numbness, the mind slows down, and thoughts and feelings lessen,” psychotherapist Jason Shiers, Dip.Psyh MBACP tells WebMD Connect to Care. “The user becomes calm and experiences peace of mind, drowsiness, and escape from their everyday reality. Once people start to get a feel for the chemically enhanced lifestyle, it is much easier for them to cope.”

3. Why do brains love opioids?

When you take opioids, you experience euphoria or feelings of extreme happiness, pleasure, and relaxation. “When these drugs bind to opioid receptors, they release dopamine, a neurotransmitter associated with pleasure and reward,” Waismann says. “This dopamine flood produces euphoria and contributes to its addictive potential.”

“In addition, opioids also block pain signals from reaching the brain, providing relief from both physical and emotional pain. Over time, the brain adapts to the presence of opioids by making less dopamine. This leads to dysphoria (a state of feeling unwell) when the drug is not taken, which increases drug-seeking behavior and can lead to addiction,” Waismann adds.

As you continue taking an opioid, your brain slowly gets used to it and fails to function normally in its absence, Cleveland Clinic notes. This creates an intense craving or urges to keep using the drug, irrespective of the harmful effects. The inability to control the use of the substance despite its negative consequences is, therefore, a key characteristic of addiction.

According to the National Library of Medicine, with prolonged use, you may develop tolerance to the drug. This means you may feel the need to take increased amounts of the drug to achieve the same intensity of euphoria. This is also a sign of addiction.

Additionally, the continuous misuse of opioids may lead to psychological and physical dependence. Psychological dependence is when your thoughts, emotions, and activities are dominated by the use of drugs. Physical dependence is when your body has become accustomed to drug use to such a degree that if you reduce or stop taking the drug, you experience unpleasant withdrawal symptoms. 

4. Why are opioids so addictive?

“The pleasure derived from opioids' stimulation of the brain's natural rewards system is such a strong motivator that it creates a powerful desire to repeat this experience again and again,” Wenner says. “The brain also releases dopamine when exposed to opioids, a chemical messenger that helps people learn new things and remember what they've already learned. When someone gets addicted to opioids, the brain releases more dopamine than normal, which triggers an intense feeling and drives them to seek the next dose.” 

Accessibility and legal status both contribute to the widespread popularity of opioid drugs. In some cases, addiction begins when you get a long-term prescription for chronic pain medication. In addition, users also often obtain opioids from friends and family members who have pills left over from old prescriptions.

“Opioids are the drug of choice for so many addicts for various reasons,” addiction specialist and psychoanalyst Colin McDonnell, MA tells WebMD Connect to Care. “Primarily, they are very easy to access without fear of criminal charges. Being a legal, controlled substance, they also do not carry the stigma normally associated with other drugs. Using them can be very easy to explain to others. The effects on the body are also much easier to hide from others than more visibly intense drugs.”

5. Why are opioids so addictive while other drugs are not?

“Opioids are so addictive because they hijack the brain's natural reward pathways,” Waismann says. “Dopamine is a neurotransmitter that plays a key role in addiction and pleasure-seeking behaviors. When opioids activate the dopamine receptors, they create an intense feeling of euphoria that can be powerfully addictive.”

Opioids also trigger the release of “feel-good hormones” or endorphins, states the Mayo Clinic. Endorphins not only help reduce your pain perception, but also boost the feelings of pleasure–leading to a temporary but strong sense of well-being. When the effect of opioids fades away, you may feel the urge to get those feelings back quickly. This is the first step towards the path of addiction.

“When used as directed by a physician, opioids are designed to deliver pain relief little by little, over a 12-hour period,” James Pratty, MD, a Psychiatrist and Medical Director at Behavioral Health for Brand New Day, tells WebMD Connect to Care. “However, when abused, such as by crushing or chewing the pills, taking them with alcohol, or using them without a physician’s prescription, opioids can flood the brain with dopamine and the risk of overdose becomes very great.”

According to the National Library of Medicine, opioid addiction is a long-lasting disease that may cause significant social, financial, and health-related issues. It’s also important to know that opioids can cause addiction even when they are prescribed appropriately by a doctor and taken as advised.

The exact cause of opioid addiction is not known, however, a combination of genetic, environmental, and lifestyle factors seem to play a role. Many genes that are involved in the body’s internal system of regulating pain and reward system, may also play a role in opioid addiction. Variations in the genes that decide the structure of opioid receptors in your body have been researched as a genetic risk factor for opioid addiction. Scientists believe that structure and function of opioid receptors may influence how your body reacts to opioids.

According to Mayo Clinic, psychological, environmental, and lifestyle factors that may increase the risk of opioid addiction are:

  • A lack of employment
  • Financial issues
  • Young age
  • A history of substance misuse
  • A family history of substance misuse
  • Living in a high-risk environment
  • Meeting high-risk people regularly
  • An unstable professional, social, or personal life
  • Stressful circumstances 
  • A history of severe depression or anxiety
  • Risk-taking or thrill-seeking behavior
  • Heavy tobacco use

6. Can you get addicted to opioids from one use?

“It is not common, but it is possible to develop an addiction to opioids after just one use,” Waismann says. “This can occur because of the euphoric feeling or "high" that is associated with the drug. Additionally, people may self-medicate with opioids in order to numb unwanted feelings. The desire to relieve these feelings can lead to multiple uses and then addiction.”

“Opioid addiction is a serious problem that can profoundly impact an individual's life. If you or someone you know is struggling with opioid addiction, it is essential to seek professional help,” Waismann adds. 

Get Help Now

Dealing with addiction on your own is extremely difficult. Don’t hesitate to reach out for professional help to give you freedom from opioid dependency.

According to the American Psychiatric Association, many treatment methods are available if you want to quit opioids. One of the most effective methods is Medication-Assisted Treatment or MAT. It not only involves the use of medicines to detoxify you of opioids, but it also utilizes counseling and behavioral therapies to help cope with the treatment and learn new lifestyle habits.
Three medications approved by the FDA for treating opioid addiction are:

  • Methadone
  • Buprenorphine
  • Naltrexone 

If you or a loved one is struggling with opioid addiction, WebMD Connect to Care Advisors are standing by to help.

Treatment & Resources for Opioid Addiction