Opioids: Key Differences Between Physical Dependence and Addiction
The terms "addiction" and "physical dependence" are often used interchangeably, especially in discussions around opioids. Those discussions are frequent these days, since the National Institute on Drug Abuse (NIDA) reports that every single day, more than 115 people die in the United States from overdosing on opioids, which include prescription pain relievers, heroin, and synthetic opioids, including fentanyl.
So how did we get here? Hearken to more than two decades ago, when the pharmaceutical industry essentially told physicians and other healthcare professionals that "It's OK. Your patients won't become addicted." As we now know, that just wasn't true.
Some states, including Virginia, are currently taking aim at pharmaceutical companies. The state's attorney general alleges that Purdue Pharma, maker of OxyContin, created the current opioid crisis and is suing the company.
Words were confusing
"Back then, if someone was in chronic pain, we treated them with opioids," said Andrew Saxon, M.D., chair of the Council on Addiction Psychiatry of the American Psychiatric Association, in a telephone interview with HealthCentral.
"It was sometimes very confusing," he says. "The term 'opioid dependence' was used in that era to denote physical dependence which incorporates tolerance and withdrawal. It also denotes the full behavioral syndrome of 'opioid addiction.' That includes tolerance and withdrawal but also behaviors such as taking more drug than intended and failing to fulfill role and relationship obligations."
- Tolerance is generally defined as when a person no longer responds to a drug as they did when first taking it.
- Withdrawal is a constellation of symptoms that occur after chronic use of a drug is reduced or stopped. It can vary from drug to drug and from person to person in harshness and longevity.
How definitions evolved
"It was commonplace to confuse simple physical dependence, which any patient would have if taking opioids repeatedly for chronic pain, with the full syndrome of addiction," he says.
The words may have changed but the effect of opioids on the body hasn't. "If you're being treated with opioids for pain and you're on them for a substantial time, more than a few weeks, you may develop tolerance and then have withdrawal if you stop the medication," says Dr. Saxon.
In 2013, the DSM-5 was published — the Diagnostic and Statistical Manual of Mental Disorders that defines and classifies those disorders. Language was also changed from "opioid addiction" to "opioid use disorder."
A concept paper from the American Society of Addiction Medicine and the American Medical Association reports that a 493 percent surge occurred in opioid use disorder diagnoses from 2010 to 2016.
Defining terms now
The NIDA explains the subtle nuances between physical dependence and addiction, echoing Dr. Saxon on some points:
- Addiction: compulsive drug use despite harmful consequences; inability to stop using a drug; failure to meet work, social, or family obligations; and, sometimes (depending on the drug), tolerance and withdrawal
- Physical dependence: when the body adapts to the drug, needs more to achieve a desired effect, i.e., tolerance; causes physical or mental symptoms if it's stopped, i.e., withdrawal
Think of it this way: Physical dependence isn't addiction, but it can be part of addiction.
An internationally-recognized expert on addiction, Charles P. O'Brien, M.D., in the psychiatry department at the Perelman School of Medicine, University of Pennsylvania, defines these differences between the two terms:
- Addiction: is abnormal and classified as a disease; manifests as uncontrollable cravings, inability to control drug use, compulsive drug use, and use despite doing harm to oneself or others
- Physical dependence: occurs when the body relies on an external source of opioids to prevent withdrawal. Physical dependence is predictable, easily managed with medication, and is ultimately resolved with a slow taper off of the opioid. Physical dependence to opioids is normal and expected and a distraction from the real problem — addiction — he says.
Dr. O'Brien warns that the word "dependence" may be erroneously used in conversations around both physical dependence and addiction, which may indeed be a matter of semantics, but can lead to confusion.
Patients do have choices
Times have sure changed from those pre-2013 days, says Dr. Saxon.
"The belief then was that if you were a compassionate and caring physician, and your patient had chronic pain, prescribing opioids was the right thing to do — so they wouldn't suffer. Now we don't think medication is always the first line of treatment."
Taking a cautionary stance is especially relevant because no one has a crystal ball.
"We don't know how many people will develop addiction when given opioids," he says. "And because we don't know who will develop a problem, it's sometimes better not to use anything in the first place."
One modality that is being used: psychotherapy.
"It helps help people 'think differently' about the meaning of pain," he says. "You have it because it's a signal to you that you're in danger, and true, when things go awry in the body, you can have pain.
Metaphorically, you want to 'roll yourself up into a ball' to protect yourself, to try everything you can not to harm that area of the body." However, many forms of chronic pain are danger signals gone awry, and it is perfectly safe for the patient to be physically active despite the pain, he says. Increased physical activity can actually help diminish the sensation of chronic pain for many people.
Opioids simply aren't the end-all-be-all, he says. In fact, a study published in March 2018 in the Journal of the American Medical Association was a bombshell of sorts, concluding that: "Treatment with opioids was not superior to treatment with nonopioid medications for improving pain-related function over 12 months. Results do not support initiation of opioid therapy for moderate to severe chronic back pain or hip or knee osteoarthritis pain." The study indicates that the first step for nonopioid treatment was acetaminophen (paracetamol), or a nonsteroidal anti-inflammatory drug.
"Opioids may be indicated if you've tried everything else and nothing's working," says Dr. Saxon. "But when you do prescribe them, and a patient says: 'This isn't enough,' that can be a sign that a patient is going to be prone to developing addiction or opioid use disorder."
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