Chronic pain and psychiatric illness: Managing comorbid conditions

Pain is one of the most common symptoms for which patients seek medical care, with an associated estimated annual cost of $600 billion.¹ Using a multimodal approach to care—thorough evaluation, cognitive-behavioral and psychophysiological therapy, physical therapy, medications, and other interventions—can help patients effectively manage their condition and achieve healthier outcomes.

Evaluating a patient with pain
When developing a safe, comprehensive, and effective treatment plan for patients with chronic pain, first perform a thorough history and physical exam using the following elements:

Pain history. The PQRST mnemonic (Table 1) can help you obtain critical information and assist in determining the appropriate diagnosis and cause of the patient’s pain complaints.

Psychiatric history. Document the mental health history of the patient and first-degree relatives.

Medical history. Knowing the medical history could reveal comorbidities contributing to a patient’s pain complaint.

Treatment history. Listing past and current treatments for pain, including effectiveness, helps the clinician understand if an existing treatment plan should be modified.

Functional status. Document current level of daily activity, how life activities are affected by pain; strategies used to help cope with pain; level of physical and emotional support provided in home, work, and school environments; and active stressors (eg, financial, interpersonal).

Psychosocial history. Document historical information related to coping skills, trauma history, family of origin, abuse, interpersonal relationships, social support, and academic and vocational functioning.

Substance use or abuse. Assess for use of controlled substances (ie, early refills; lost medications; obtaining medications from multiple prescribers, friends, families, or strangers; use of prescribed and non-prescribed medications for non-medical and medical purposes), nicotine, alcohol, illicit substances, and caffeine. A thorough inventory can help to identify substances a patient is using that could affect daily functioning and pain level.

Behavioral observations. Assessing mental status (eg, insight, pain behavior, co­operation) can be useful. Paying attention to pain behaviors, such as complaints of pain, decreased activity, increased medication intake, or altered facial expressions or body posture, can help the clinician gain insight to the extent that pain affects the patient’s quality of life.

The information gathered in the patient evaluation can be used to design a multimodal treatment plan to achieve maximum effectiveness.

Assessing psychiatric illness
Current approaches to pain evaluation and treatment recommend use of a biopsychosocial orientation because psychological, behavioral, and social factors can influence the experience and impact of pain, regardless of the primary cause.² A comprehensive psychiatric evaluation, diagnosis, and treatment plan should consider the broader context in which a patient’s pain occurs.

Regarding psychiatric illness, past and current symptoms, treatment history, and risk assessment should all be included. Using the “AMPS approach” (Figure)³—assessing Anxiety, Mood (depression and mania), Psychotic symptoms (paranoid ideation and hallucinations), and Substance use—helps screen for comorbid psychiatric conditions in patients with chronic pain.

Sleep assessment
Chronic pain patients often experience significant sleep disturbance that could be caused by physiological aspects of the pain condition, environmental factors (eg, uncomfortable bedding), a comorbid sleep disorder (eg, sleep apnea), a psychiatric disorder, or a combination of the above.

Obstructive and central sleep apnea are characterized by nighttime hypoxia, which leads to frequent disruption of the sleep-wake cycle and often manifests as daytime fatigue, irritability, depression, drowsiness, headaches, and increased pain sensitivity. Changes in sleep arousal can lead to neuro­psychological changes during the day, such as decreased attention, memory problems, impaired executive functioning, and reduced impulse control.

Screen patients for central and obstructive sleep apnea before prescribing opioids or benzodiazepines for pain because these medications can cause or exacerbate underlying sleep apnea. Although many screening tools, such as the Epworth Sleepiness Scale, assess daytime somnolence,⁴ the STOP-BANG questionnaire is a quick, validated, and efficient screening tool that often is used to assess sleep apnea risk^5,6 (Table 2). The presence of ≥3 risk factors identifies patients at increased risk and warrants consideration for further workup by a sleep specialist.^7,8

Pharmacotherapy for chronic pain
Non-opioid medications. Pain can be broadly categorized as neuropathic or nociceptive. Neuropathic pain can be described by patients as numbness, burning, electric-like, and tingling, and is associated with nerve damage. Nociceptive pain commonly is described as similar to a toothache with descriptors such as stabbing, sharp, or a dull aching sensation; it is often, but not always, associated with acute injury or ongoing trauma to tissue. Drug treatment is most successful when the appropriate class of medication is matched to the specific type of pain.

Nociceptive pain often is successfully treated with non-steroidal anti-inflammatory drugs and acetaminophen. Non-selective COX inhibitors (eg, ibuprofen, indomethacin, ketorolac) and COX-2 selective inhibitors (eg, celecoxib) have been associated with cardiovascular, gastrointestinal, and renal disease; acetaminophen is associated with liver dysfunction.^9-11 However, the absolute risk for complications in healthy patients is low.¹² To minimize risk, use these agents for the shortest duration and at the lowest effective dosage possible.