Chronic nonmalignant pain: How to ‘turn down’ its physiologic triggers

• substance abuse
  
• nonadherence with treatment
  
• withdrawal from support systems
  
• incapacitating emotional states, such as marked dysphoria, anger, or anxiety.
  

Low self-efficacy is a predictor of perceived disability resulting from persistent pain.¹⁹ Patients with limited coping ability may experience despair and chronic pain is a risk factor for suicide.²⁰

Table 3

Biopsychosocial assessment of chronic pain patients: 3 components

Somatic factors
Determine pain onset/duration, location, quality, intensity, associated features, aggravating and alleviating factors
Single-dimension pain rating scales, such as Numeric Rating Scale or Visual Analog Scale
Review prescribed and over-the-counter analgesic use (adherence, excess use, impact on functional adaptation)
Psychological factors
Mood and affect, cognitive content and processes, coping skills
Psychiatric comorbidities (substance abuse/dependence; anxiety, sleep, and somatoform disorders; delirium; depression; sexual dysfunction)
Suicide risk assessment
Multidimensional pain rating scales, such as Coping Strategies Questionnaire or Multidimensional Pain Inventory
Social factors
Impact on relationships, including capacity for intimacy, mutuality, and sexuality
Impact on activities of daily living, vocational and recreational functioning
Determine functions patient can perform despite pain
Source: Adapted from reference 3

CASE CONTINUED: Multifaceted treatment

You prescribe amitriptyline, 20 mg at bed-time, for pain and refer Mrs. A for cognitive-behavioral therapy (CBT). The emphasis of therapy is to identify affective states and cognitive distortions that are temporally related to pain exacerbations, to develop coping skills to deal with stressors, and to effectively express her anger. Mrs. A learns relaxation techniques and self-hypnosis to reduce distress. These measures help reduce her pain severity ratings to 3 on a 10-point scale. She also participates in physical therapy and yoga classes, which increase her endurance.

Psychiatrists’ role in treatment

Many chronic nonmalignant pain syndromes—including arthritic conditions, back pain, and fibromyalgia—are tenacious and not easily cured. Treatment goals are to relieve pain and maximize the patient’s functioning and quality of life while minimizing risks of iatrogenic harm. As part of a biopsychosocial approach to care:

• diagnose and treat psychiatric comorbidities
  
• assess responses to treatment interventions
  
• refine treatment measures when patients do not achieve functional and adaptational goals
  
• initiate pharmacologic interventions for pain
  
• address subsyndromal emotional and cognitive impediments to functional restoration.
  

Psychotherapy. Meta-analyses of patients with chronic low back pain, rheumatoid arthritis, osteoarthritis, fibromyalgia, and unspecified somatic pain found that CBT is significantly more effective than wait-listing in reducing pain severity ratings and pain expression and in improving coping strategies.^21-24 These analyses had limitations, however. Sample sizes were small because it is often difficult to retain patients in trials of complex, multicomponent treatment approaches.²³ In addition, measures of healthcare utilization, analgesic use, and resuming work after treatment were sparse in several studies.

In initial CBT sessions, the goal is to elicit the patient’s:

• perception of pain
  
• life situations
  
• beliefs about his or her life, relationships, and the future
  
• coping measures.
  

The focus then shifts to assessing the accuracy and usefulness of the patient’s beliefs and coping strategies and to replace maladaptive ones.

Self-regulatory techniques—including relaxation training, biofeedback, and hypnosis—can facilitate relaxation and “turn down” the physiologic triggers that cause and perpetuate pain.^25,26 Hypnosis can lead to dissociative states that modify how a patient experiences pain. There is modest evidence that self-regulatory techniques are effective for treating pain.^27,28

Pharmacotherapy. Multiple pathophysiologic mechanisms—including ion channel up-regulation, spinal hyperexcitability, and descending neurotransmitter pathway impairment—play a role in chronic pain states. Several classes of psychoactive agents can mitigate pain (Table 4), and some psychotropics are FDA-approved for specific pain conditions (Table 5).

Individualize medication selection, considering:

• cost
  
• ease of use
  
• tolerability
  
• interactions with coadministered medications
  
• clinical comorbidities.
  

Opioids, long the mainstay of treatment for acute and cancer-related pain, also are used to treat chronic nonmalignant pain. Whether long-term opioid use improves quality of life and adaptive functioning of chronic pain patients remains controversial.²⁹ Psychiatric care may be necessary if:

• opioid therapy fails
  
• patients become dependent on escalating doses of opioids.
  

Patients may need opioid detoxification and prudent use of co-analgesics to restore their function.^3,30

Antidepressants influence pain by blocking monoamine reuptake. Those that influence noradrenergic and serotonergic transmission may have greater analgesic effects than those that affect serotonin or norepinephrine reuptake alone.^31-33

Anticonvulsants mitigate pain by influencing sodium or calcium channel regulation, GABA activity, or combinations of the 3.

In randomized controlled trials that included patients with diabetic and postherpetic neuropathies:

• one-third of patients achieved ≥50% pain relief with tricyclic antidepressants (TCAs) or anticonvulsants
  
• adverse effects were slightly more common with TCAs.^34,35
  

Anticholinergic and alpha-adrenergic side effects may limit TCAs’ usefulness.

Because antidepressants and anticonvulsants have different presumed mechanisms of action for pain relief, anticonvulsants might be useful for patients whose pain persists despite optimal antidepressant dosing or for whom antidepressants are in-tolerable. Alternately, coadministering antidepressants and anticonvulsants might capitalize on complimentary mechanisms of action. With coadministration, lower doses may be sufficiently analgesic and avoid adverse effects.