DSM-IV-TR Diagnostic Criteria
Pain in one or more anatomical sites is the predominant focus of the clinical presentation and is of sufficient severity to warrant clinical attention.
The pain causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.
Psychological factors are judged to have an important role in the onset, severity, exacerbation, or maintenance of the pain.
The symptom or deficit is not intentionally produced or feigned (as in factitious disorder or malingering).
The pain is not better accounted for by a mood, anxiety, or psychotic disorder and does not meet criteria for dyspareunia.
Pain disorder associated with psychological factors
Pain disorder associated with both psychological factors and a general medical condition
- Acute: duration of less than 6 months.
- Chronic: duration of 6 months or longer.
(Reprinted, with permission, from Diagnostic and Statistical Manual of Mental Disorders, 4th edn. Text Revision. Washington DC: American Psychiatric Association, 2000.)
Pain syndromes are categorized based on whether they are associated primarily with (1) psychological factors, (2) a general medical condition, or (3) psychological factors and a general medical condition. The second categorization is not considered to be a mental disorder but is related to the differential diagnosis. This classification of pain appears to be superior to previous systems because it takes into account underlying physical disease to which the patient may be reacting in an exaggerated form. Thus the clinician can avoid the either-or dualism that prevailed earlier. Most patients probably have some degree of physical disease that initiates painful sensations, and it is the response to these sensations that constitutes abnormal illness behavior.
Pain is the most common complaint with which patients present to physicians. It is estimated that the cost to the United States economy (direct and indirect costs) for pain related disability is in the range of 100 billion dollars. A well-constructed European epidemiologic study found that pain disorder is the most common of the somatoform disorders; The incidence over one year was 8.1% and life-time incident was 12.7%. According to one U.S. study, 14% of internal medicine private patients had chronic pain. Those who seek medical care for chronic pain may be a subgroup of those who experience it.
Pain is a heterogeneous disorder. No single etiologic factor is likely to apply to all patients. Among the proposed etiologies are psychodynamic formulations that pain represents an unconsciously determined punishment to expiate guilt or for aggressive feelings or an effort to maintain a relationship with a lost object. Consistent with psychodynamic theories, some patients with pain syndromes demonstrate masochistic, self-defeating personality characteristics.
Another etiologic theory proposes that pain represents learned behavior. It is hypothesized that the patient’s previous experiences of personal pain have led to changes in other persons’ behavior, thereby reinforcing the experience of pain and pain behaviors. Consistent with this theory are observations that some pain patients have experienced medical illnesses or injuries associated with pain or lived in childhood homes where disease, illness, and pain were present. It has also been proposed that pain represents a somatic expression of depression. There is a high incidence of depression in pain patients and among their family members and depression often precedes pain symptoms. Another important dysphoric affect is anger which often precedes the onset of chronic pain symptoms and/or be an important factor in maintaining the pain complaints.
Because pain is a subjective symptom, it is easy to simulate. A substantial percentage of litigants who claim pain have been shown to exaggerate or outright malinger the symptom.
No studies have related genetic factors to pain disorder.
Patients who repetitively seek treatment for pain may represent a subset of individuals with pain who have certain patterns of illness behavior, rather than reflecting psychological characteristics of all persons who have pain per se. Pain syndromes include fibromyalgia, atypical facial pain, chronic pelvic pain, chronic low back pain, recurrent or persistent headaches, and so on. These patients’ descriptions of pain are often dramatic and include vivid descriptions such as “stabbing back pain” or “a fire in my belly.”
Psychological tests such as the MMPI are often used to evaluate pain patients. Common findings include somatic preoccupation, underlying depression or anxiety, and a tendency to deny psychological symptoms. The McGill Pain Questionnaire, a patient self-report test, frequently discloses that the patient uses idiosyncratic and colorful words to describe his or her pain experience.
In experimental settings, pain disorder patients often have a lower threshold for pain than do normal subjects. It is difficult to determine if this greater sensitivity is the result of physiologic or psychological differences.
Elucidation of brain mechanisms involved in pain is evolving rapidly through techniques of functional neuroimaging. Interpretations of findings remain at the investigational stage but there is promise for future clinical applications. Available information, to date, implies that the anterior cingulate cortex plays a critical role in the emotional component of pain. Chronic pain syndromes have been associated with increased activity in the somatosensory cortices, anterior cingulate cortex and the prefrontal cortex and decreased activity in the thalamus.
No common symptoms or psychological features describe all pain patients. Despite this heterogeneity, pain patients share some features. Pain patients tend to focus on their pain as an explanation for all their problems; they deny psychological problems and interpersonal problems, except as they relate to pain. These patients frequently describe themselves as independent, yet observations of them suggest that they are dependent on others. They frequently demand that the doctor remove the pain, and they are willing to accept surgical procedures in their search for pain relief. “Doctor shopping” is common. Family dynamics are altered in a manner that makes the pain patient the focus of the family’s life.
Pain patients often see themselves as disabled and unable to work or perform usual self-care activities. They demand, and often receive, a large number of medications, particularly habituating sedatives and analgesics. The pain persists despite chronic and often excessive use of these medications, on which these patients may become both psychologically and physiologically dependent.
Differential Diagnosis (Including Comorbidity)
The differential diagnosis of pain disorder inevitably involves underlying disease processes that may cause the pain. The coexistence, however, of such disease does not rule out the diagnosis of pain disorder if psychological factors are believed to exacerbate or intensify the pain experience. Patients with chronic pain have a high frequency of comorbid psychiatric disorders, including depressive spectrum disorders, anxiety disorders, conversion disorder, and substance abuse disorders. Many of these patients meet diagnostic criteria for a personality disorder, most commonly dependent, passive-aggressive, or histrionic personality disorders.
The treatment of acute pain disorder is generally aimed at reducing the patient’s underlying anxiety and the acute environmental stressors that exacerbate the patient’s personal distress. Psychiatrists are much more likely to be involved in the evaluation than in the treatment of chronic pain syndromes. Psychiatrists may see patients with these syndromes on referral or as a part of a multidisciplinary pain treatment team. Because patients with chronic pain often resent implications that their pain has psychological causes, psychiatrists are usually most effective when serving as consultants to other health care providers. Chronic pain characteristically leads to changes in behavior that are reinforced by environmental factors. These patients have often assumed an identity as a chronically disabled person and have taken a passive stance toward life. The major objectives for treatment must be to make the patient an active participant in the rehabilitation process, to reduce the patient’s doctor shopping, and to identify and reduce reinforcers of the patient’s pain behaviors.
Patients with chronic pain have generally received prescriptions for multiple analgesics, often including opiate medications. These patients may demand increasingly larger dosages of medication if they have become dependent, and they may exhibit considerable resistance to discontinuing or decreasing medications. Clinicians must explain to these patients that medications have not been successful in relieving pain and that other techniques are indicated. Medications may play a limited role as part of the overall treatment. As a general rule, nonsteroidal anti-inflammatory agents rather than opiates should be the first choice in medication. When more potent analgesics are indicated, they should be prescribed on a fixed-dosage schedule rather than on a variable-dosage schedule. Patients who are prescribed medication on an as-needed basis are much more likely to engage in pain behaviors to indicate the need for medication. The use of a fixed-dosage schedule enables the extinction of pain behaviors as a means of communicating the need for more medication. Patients who have been prescribed opiates either over a long period of time or in high dosages may require a detoxification program rather than abrupt discontinuation.
Antidepressant medications are often helpful to pain patients, particularly when symptoms of major depression are present. Clinical experience suggests that dual-reuptake inhibitors (serotonin and norepinephrine) such as duloxetine or venlafaxine are more effective than the specific serotonin reuptake inhibitors. Tricyclic antidepressants such as nortriptyline continue to have a role in the treatment of chronic pain patients and patients may have a beneficial response to dosages lower than those used to treat depression. Caution must be utilized in prescribing potentially habituating medications (e. g., benzodiazepines) for sleep or anxiety because these patients are at high risk for prescription drug abuse/dependency. Anecdotal reports suggest that “off label” use of the atypical antipsychotic medications (e. g., olanzapine) or antiepileptic medications (e. g., gabapentin) may be useful in some patients.
Insight-oriented psychotherapy may be helpful for the few patients who have identified unconscious conflictual issues. However, the vast majority of patients with chronic pain are not psychologically oriented, and insight psychotherapy is not efficacious. Supportive psychotherapy may be helpful in reassuring and encouraging these patients and in improving their compliance with other aspects of the treatment program. As a general rule, behavioral therapy is the most effective type of psychotherapy in the treatment of pain disorders. Both operant conditioning and CBT are widely used (see Chapter 10).
Operant conditioning is based on the concept that certain learned behaviors develop in response to environmental cues. Thus the patient has learned a variety of pain behaviors that are elicited in certain situations. Patients often communicate their pain to others (e. g., by grimacing) to elicit responses. Behavioral analysis identifies both the stimuli and the response-altering reinforcements to these behaviors. The behavioral therapist works to substitute new behaviors for previously learned pain behaviors. Patients are praised for increasing their activity and are not rewarded for pain. Behavioral techniques are most useful when the patient’s family is included in the overall treatment program, so that pain behavior is not reinforced when the patient returns home.
CBT techniques focus on identifying and correcting the patient’s distorted attitudes, beliefs, and expectations. One variety of this treatment involves teaching the patient how to relax or refocus thinking and behavior away from the preoccupation of pain.
Chronic pain patients are often disabled and receive fragmented medical care from multiple specialists. A pain clinic provides comprehensive integrated medical care. These clinics seem to work best when a strong behavioral therapy component is associated with a comprehensive evaluation and when treatment interventions include the patient’s spouse, family, and when applicable, employer. The therapeutic focus of pain clinics is to transfer the patient’s sense of responsibility for treatment from physicians and medications to the patient himself or herself and to work actively within a rehabilitation program to restore self-care and social and occupational functioning. The focus is on rehabilitation more than it is on pain relief. The message provided is that the patient must learn how to “play hurt.” These techniques are often useful for short-term improvement in function. Limited data are available regarding long-term outcome.
Treatment of Comorbid Disorders
Treatment of the symptom of pain often involves attention to coexisting or secondary psychiatric disorders. Major depression should be treated pharmacologically, and anxiety disorders should be treated as indicated with relaxation techniques, behavioral therapy, or pharmacotherapy. Substance abuse problems frequently require detoxification and appropriate rehabilitation techniques to maintain abstinence. Patients whose pain appears to be related to symptoms of posttraumatic stress disorder may require treatment for that disorder; specialized treatment programs for the survivors of violent crimes or sexual abuse may be indicated.
Complications/Adverse Outcomes of Treatment
Pain disorder patients are at risk for iatrogenic addiction to opiate compounds or benzodiazepines. These patients often sabotage their treatment programs, proclaim that psychiatric treatment was not successful, and then use this as proof that their pain has a physical cause.
Surprisingly little information is available concerning prognosis for chronic pain patients. Clinicians may see patients who have complained of chronic pain for many years, even decades, and who, in the interim, have been subjected to multiple surgical procedures and have experienced iatrogenic complications. Factors known to be of poor prognostic significance include ongoing litigation related to the pain (e.g., when the illness or accident that caused the pain was associated with a potentially compensable injury), unemployment, loss of sexual interest, or a history of somatization prior to the onset of chronic pain.
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