Many patients are often confused as to how they can be dependent on a drug, such as an opioid, but not be addicted to it. The distinction is essential for patients and caregivers to understand. This is why recent evidence-based literature clearly defines the difference between addiction and physical dependence in drug use.
Physical dependence is when the body requires a specific dose of a particular drug, such as a prescription opioid1, in order to prevent withdrawal symptoms. This typically happens when a patient uses a drug long-term (six months or longer) to manage pain associated with a medical condition. In this time frame, the body builds up a natural tolerance to the medication and becomes dependent on it to maintain status-quo. When a patient is prescribed drugs in this capacity, a medical doctor oversees the patient to wean them off the medication in a way that without the risk of withdrawal or desire to continue using it.
Substance use disorder (SUD), or addiction, is classified as abnormal and is defined by the DSM-52 as a chronic, treatable illness. SUD can have devastating, life-long consequences if not addressed. SUD results in compulsive behaviors that manifest as cravings, an inability to control use, and continued use of the drug despite its harmful consequences. SUD can occur separately from physical dependence, although in the case of opioid use, a patient is also typically physically dependent on the drug. It is important to understand and discuss the risks of drug dependence with your prescribing doctor.
Physical dependence affects that part of the brain that oversees autonomic body functions, such as breathing. While the patient who is physically dependent may experience some euphoria while using the drug, the reward center in the brain remains “offline,” and the patient is still capable of managing impulses and making decisions in their best interest. In other words, the patient still has control over their use.
In contrast, with SUD, a patient’s actions are directed primarily by an overwhelming need to accommodate the brain’s reward center, and the part of the brain that guides self-control and decision making is directly impeded. A patient with a SUD begins to lose the ability to effectively prioritize their well-being over the continued use of the drug. Because of the direct effects on the brain, an addicted patient will often act out of character and develop an inability to determine whether and when their use has become problematic and uncontrollable.
In the case of both physical dependence and SUD, the same brain receptors are affected, but with different effects that have specific (and increasingly severe) health consequences:
It is important to keep in mind that physical dependence can occur without the patient developing a SUD.
There are several factors that can predict a person’s susceptibility to SUD:
Additionally, undiagnosed or untreated mental health issues, such as depression, can be a predictor of eventual reliance on substances for self-management of negative affective states.
Before any opioid regimen is prescribed, both the patient and doctor must work together to develop a plan in case the person patient begins to show signs of SUD. In such cases, the prescribing physician can promptly transition in the patient off of the medication and have them evaluated and treated for SUD.