For purposes of this article, pain will be used according to the definition used by the International Association for the Study of Pain:
“Pain is an unpleasant sensory and emotional experience that is associated with actual or potential tissue damage or described in such terms.”
Most definitions of pain include the notion that pain is a subjective experience; that is, that individuals experience pain differently, and people who have very similar injuries may have entirely different perceptions of pain. The aspects of pain include:
- The sensation of pain, which describes the physical process of pain being conveyed to the brain by sensory neurons. This is a purely physical process.
- The perception of pain, which describes the subjective interpretation of the sensation of pain including its location, intensity, nature, and any other emotional and cognitive facets associated with it.
There is quite a bit of literature and research on pain, and it is clear that many of the definitions of various types of pain and the understanding of the subjective nature of pain, despite the presence of so much literature, is still lacking. One designation that is commonly observed in descriptions of the different types of pain is the designation of acute and chronic pain.
Acute Pain vs. Chronic Pain
An important designation in understanding pain is the designation between acute pain and chronic pain; however, these remain relatively poorly described conditions. To keep things relatively straightforward for this article we will describe acute pain as being an adaptive response of the person’s protective system.
- This adaptive response motivates the individual to consciously engage in certain protective actions to promote their safety, protection from damage, healing, and recovery.
- This adaptive response also results in the autonomic nervous system aiding in recovery and healing (the autonomic nervous system is a part of the peripheral nervous system [outside of the brain and spinal cord] that is not under voluntarily control).
- Typically, most sources will include some aspect of potential injury or actual injury in the definition of acute pain.
The definition of chronic pain is also relatively poorly defined. Most sources consider any ongoing pain lasting longer than six months to be defined as a chronic pain syndrome (CPS); however, others have used three months as the minimum timeframe to diagnose chronic pain. Still other authors suggest that any pain that lasts longer than would reasonably be expected for healing should be considered chronic pain.
Thus, most sources describe acute pain as being the result of some injury and triggering adaptive responses in the individual that promote healing and recovery, whereas chronic pain is pain that continues for a specified time period (three or six months) or continues long after the expected healing process should be complete. Obviously then, any type of acute pain from injury could develop and become part of a chronic pain syndrome if it persists for specific time period or beyond what would be a typical expected period of recovery for that type of injury. Because there is no objective way to actually measure a person’s pain or to determine the validity of the subjective experience of pain in anyone, most diagnostic systems of pain rely on the self-report of the individual with the complaint. This complicates measuring, defining, and validating any person’s complaints of pain.
There are a number of other types of pain, definitions related to pain, and descriptions of how the subjective experience of pain interacts with stress, emotions, and expectations. Individuals interested in learning more about pain are encouraged to visit the websites of organizations such as the International Association for the Study of Pain and the American Academy of Pain Medicine.
Chronic Pain (CPS)
CPS is a syndrome that has resulted in a number of costs, both to society and to the individuals who suffer from it. People who suffer from CPS often become dependent on drugs, other medical treatments, and are unable to satisfactorily engage in aspects of living, such as a career, social activities, recreation, etc. CPS also forces a tremendous burden on society in terms of medical costs, lost productivity, and disability and welfare payments to individuals who are unable to support themselves.
Any number of conditions can be associated with chronic pain. Some of the top conditions associated with chronic pain include issues with the back that produce back pain, headaches, joint pain from arthritis or other conditions, abdominal pain, and chest pain.
One issue that is agreed on is that CPS is a constellation of different syndromes that often do not respond to a mere medical model of care. In the medical model of care:
- The physician focuses on the dysfunction within the patient using a problem-solving strategy.
- The problem-solving strategy is accomplished by the gathering of a medical history, performing a complete physical examination, and using specific diagnostic tests to provide the cause of the complaint and then identify a specific treatment for the illness, injury, or disease.
- The specific treatment for CPS may be surgery, medication, or some other medical intervention.
The problem often observed in individuals with chronic pain is that the medical model approach of treatment alone does not significantly reduce the subjective experience of pain in individuals who have CPS. Thus, CPS is best managed by using a multidisciplinary approach that includes different types of physicians, psychologists, specialized nurses, and other specialized treatment professionals, such as occupational therapists, physical therapists, etc. This means that individuals with CPS will often be exposed to a number of different treatments, including:
- Medications and other medical interventions
- Psychological interventions for pain, such as learning muscle relaxation, stress reduction, and other proactive interventions designed to relieve stress and induce relaxation
- Lifestyle changes that can include changes to diet, exercise habits, sleeping habits, etc.
- Targeted therapies to strengthen the individual that can reduce the experience of pain, such as exercise programs, physical therapy, occupational therapy, etc.
- Vocational rehabilitation to assist the individual to be more efficient at their job or to find more suitable work
A medical model approach to the treatment of CPS is often the prescription of various medications, particularly narcotic medications.
Narcotic medications are all developed from specific substances or analogs of substances that originate from the poppy plant, hence the alternative names opiate or opioid medications, as all narcotic medications are all related to opium and substances derived from opium. Narcotic medications include such familiar medications as morphine, Vicodin, Norco, codeine, and OxyContin as well as heroin and other street drugs.
All narcotic medications bind to specialized receptors in the brain that have an affinity for naturally produced pain-suppressing neurotransmitters (e.g., endorphins and enkephalins). These medications are particularly effective at suppressing the pain threshold and lowering the subjective experience of pain in individuals who take them; however, they are also drugs that are often abused. Anyone who uses them for a significant length of time (e.g., over a period of 5-6 weeks) will inevitably develop some level of physical dependence on them.
Physical dependence consists of the syndromes of tolerance and withdrawal. Tolerance involves needing higher doses of a drug to achieve the effects that were once achieved at lower doses. Tolerance develops rapidly to narcotic medications, such as oxycodone. A withdrawal syndrome occurs when the person’s system adjusts such that it can only operate efficiently with certain levels of the drug in its tissues. When these levels of the drug in the system decline, from the person either stopping the drug or taking a lower dose of the drug, the individual’s system is thrown off and out of balance. This results in a number of negative effects that are both physical and psychological in nature.
Oxycodone, also known by the brand name OxyContin, is a narcotic pain medication that is particularly potent. It is used to treat moderate to severe pain that is expected to last for significant length of time. Thus, oxycodone at one time was a popular medication for the treatment of CPS; however, it also became a major drug of abuse. Tolerance develops rapidly to the drug, and individuals often abuse oxycodone with drugs like alcohol, resulting in high numbers of overdoses and related deaths occurring in the U.S.
While oxycodone is an effective drug to reduce the subjective experience of pain, it is also associated with high rates of abuse, the potential for serious side effects, and a serious potential for overdose in individuals who do not use it in the prescribed manner. The number of prescriptions written for oxycodone has been subject to scrutiny from the United States Drug Enforcement Administration and other governmental agencies in an effort to curb the rash of abuse and overdose associated with the drug.
It is important to understand that individuals who use oxycodone specifically for the control of chronic pain and under the strict supervision of a physician are less likely to abuse the drug than individuals who obtain the drug without a prescription and use it for purposes other than medicinal purposes. When anyone with a prescription begins using oxycodone in a manner that is not consistent with the instructions on the prescription, such as taking more oxycodone than prescribed, taking it more often than prescribed, or taking it in a manner not as prescribed, such as grinding it up and snorting it, that person is abusing the drug and at risk of developing an addiction.
The difference between a substance use disorder (an addiction) and medicinal use of the drug lies in the intent associated with using the drug. Addiction or having a substance use disorder is defined as a dysfunctional behavioral disorder where individuals use drugs for nonmedicinal means and in a manner inconsistent with accepted medical practices. Anyone who uses any drug under the supervision of a physician and within the confines of the instructions they are given would most likely not be given a diagnosis of a substance use disorder, even if they developed physical dependence on the drug.
Individuals who use oxycodone for medicinal purposes and individuals who abuse oxycodone will all likely develop physical dependence on the drug. In fact, almost anyone who uses oxycodone for any purpose regularly for a period of more than 4-6 weeks will develop some level of physical dependence on the drug. When they stop using the drug, they will exhibit some symptoms of a withdrawal syndrome.