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10 Articles in Volume 17, Issue #6
A Plea for Proper Opioid Tapering
Centers of Excellence in Pain Management: Past, Present, and Future Trends
Comorbid Pain and Childhood Obesity
Discussing Migraine With Your Patients: A Common Sense Guide for Clinicians
Justification of Morphine Equivalent Opioid Dosage Above 90 mg
Letters to the Editor: Dependence vs Addiction, Opioid Metabolism
Opioid Rotation From Opana ER Following FDA Call for Removal
Psoriatic Arthritis: Established, Newer, and Emerging Therapies
Sleep-Wake Disorders and Chronic Pain: Reciprocal and Interactive Effects
What are Nav1.7 inhibitors and how are they used in the treatment of neuropathic pain?

Sleep-Wake Disorders and Chronic Pain: Reciprocal and Interactive Effects

Since sleep and chronic pain often co-exist, each condition should be individually recognized to assure the patient receiving attention to both the medical and mental health conditions.

It is the classic chicken-and-egg problem: Which came first, pain or sleep disturbance. Both share common neurobiological systems, in particular, the central serotoninergic neurotransmission.1

The new Diagnostic and Statistical Manual of Mental Disorders (DSM-5) mandates that coexisting medical and mental conditions be independently specified when treating patients.2 This mandate acknowledges the bidirectional and interactive effects of coexisting medical and mental disorders.2 This conceptualization reflects a paradigm shift away from causal attributions, which is widely recognized in sleep medicine.

A sleep disorder, like chronic pain, may eventually become its own disease or centralized.3 The DSM-5 sleep-wake disorders are intended for use by general mental health and medical providers. There are 10 DSM-5 sleep-wake disorders: insomnia, hypersomnolence, narcolepsy, breathing-related, circadian rhythm, non–rapid eye movement (NREM) sleep arousal, nightmare, rapid eye movement (REM) sleep behavior, restless legs syndrome (RLS), and substance/medication-induced sleep disorders.2

Sleep-wake disorders and chronic pain often co-exist but require recognition so both are treated.

Prevalence of Sleep Problems

Insomnia is the most prevalent of all the sleep-wake disorders. It involves a subjective complaint of problems initiating and/or maintaining sleep or nonrestorative sleep. There are 4 main types of sleep problems that can occur in insomnia: delays in sleep onset, difficulty maintaining sleep, early awakening, and/or mixed. Insomnia is associated with a range of problems, including clinically significant impairment or distress in social, occupational, and other important areas of functioning.

About one-third of adults report having insomnia symptoms (approximately 10% to 20% report significant symptoms in primary care), with 6% to 10% having symptoms that meet the criteria for insomnia disorder.4 Approximately 5% to 10% of patients consulting with sleep clinics are diagnosed with hypersomnolence. It is estimated that about 1% of the US general population has episodes of sleep inertia.5 Narcolepsy-cataplexy affects less than 0.05% of the general population.6 Obstructive sleep apnea is very common, affecting 2% to 15% of middle-aged adults and more than 20% of older adults.7 Central sleep apnea comorbid with opioid use occurs in approximately 30% of individuals taking chronic opioids for nonmalignant pain and those receiving methadone maintenance therapy.8 From 5% to 10% of the night worker population is estimated to have a sleep disorder.9 The lifetime prevalence of sleepwalking in adults is 29%, with a past-year prevalence of sleepwalking of 4%.5 The prevalence of sleep terror episodes is approximately 2% in adults.10 The prevalence of monthly nightmares and frequent nightmares is 6%11 and 1% to 2%, respectively, among adults.12 The prevalence of REM sleep behavior disorder is approximately 0.5% in the general population.13 The prevalence rates of RLS range from 2% to 7%.14 Substance-induced sleep disorders can occur with alcohol, caffeine, cannabis, opioids, sedative, hypnotics, anxiolytics, amphetamines, stimulants, tobacco, and medications.2

Studies suggest that 50% to 70% of chronic pain patients suffer from a sleep disturbance,15-19 and at least 89% of patients seeking treatment for chronic pain report at least 1 complaint related to a disturbed sleep and wake cycle.20 Sleep disturbances differ according to the pain syndrome with which they are associated, and the data about these disturbances are irregular.21 People with chronic pain reported more chronic insomnia (48.6%) than did those without chronic pain (17.2%).22 At least 60% of rheumatoid arthritis patients report sleep problems, according to some data.23 Previous studies also have found increased arousals and sleep fragmentation in fibromyalgia patients compared to controls.24

Similarly, pain is influenced by the presence and type of sleep disturbance. Patients with chronic insomnia report more chronic pain (50.4%) than people without insomnia (18.2%),22 and several investigators have reported the presence of comorbid primary sleep disorders other than insomnia in patients with chronic pain conditions.25 Sleep apnea, RLS, and periodic limb movements in sleep are the most commonly cited ailments associated with pain.26 For example, sleep apnea is diagnosed in 17% of headache patients, which exceeds population rates.27

It is quite clear that pain impairs sleep. However, there is evidence of a bidirectional relationship between pain and sleep.28 Increased daytime pain is linked with poor subsequent nighttime sleep, and poor sleep is, in turn, associated with augmented next-day pain.28

How Are Sleep and Pain Related?

A typical sleep pattern can be divided into 5 stages based on brain-wave patterns from electroencephalography (EEG) ( Table 1). The first 4 stages are called non-rapid eye movement (non-REM) sleep and the last stage is called REM sleep. The sleep cycle lasts 100 minutes and recurs 4 to 6 times per night depending on the length of time one sleeps. REM periods are 10 minutes long early in the night but increase to up to 50 minutes by the end of sleep. In contrast, delta sleep is longest early in the night and shorter at the end of the night.29

In patients who suffer from chronic pain, a self-perpetuating cycle can be set in motion in which joint, myofascial, or musculoskeletal disease leads to fatigue, which leads to decreased aerobic exercise and physical deconditioning. As patients spend more time in bed, their basic circadian cycle is disrupted. As a result, the basic physiologic rhythm of sleep is lost. The lack of movement and sleep leads to more pain, further sleep disruption, dysphoria, and more fatigue (Figure 1). Sleep deprivation produces hyperalgesic changes according to most studies.30 Obtaining either less than 6 or more than 9 hours of sleep has been associated with greater next-day pain in the general population.31

The analgesic effect of recovery during sleep apparently is greater than the analgesia induced by compounds in healthy volunteers.32 Circadian rhythms also might be altered by the timing of various factors, including naps, bedtime, exercise, and exposure to light. Exercise and phototherapy have been used to help patients achieve better sleep.33 For example, strenuous exercise during the day may promote better sleep, as long as it’s at least 3 hours before bedtime.

How Is the Diagnosis Different in the DSM-5?

The diagnosis of primary insomnia in the DSM-IV has been renamed insomnia disorder to avoid the differentiation of primary and secondary insomnia. DSM-5 also distinguishes narcolepsy from other forms of hypersomnolence. The breathing-related sleep disorders were divided into 3 distinct disorders: obstructive sleep apnea hypopnea, central sleep apnea, and sleep-related hypoventilation. The subtypes of circadian rhythm sleep-wake disorders also were expanded to include advanced sleep phase syndrome, irregular sleep-wake type, and non-24-hour sleep-wake type. Rapid eye movement sleep behavior disorder and RLS, which fell under dyssomnia not otherwise specified in DSM-IV, now are independent disorders.2

How Do You Assess for a Sleep Disorder?

When assessing a patient for a sleep disorder, providers should begin with a careful medical history, which includes questions about the time required to fall asleep, number and length of awakenings, length of time spent in bed after awakening in the morning, and length of time after arising before feeling sleepy again, as well as questions about bed type, sleep position, and sleep description. Also, providers may want to elicit information about caffeine and alcohol intake and physical activity patterns. Some key questions should be related to specific sleep disorders, such as obstructive sleep apnea, narcolepsy, and RLS. A sleep diary, in which patients record their sleep habits on a daily basis, can be helpful.

There are several scales and questionnaires providers can use to assist in the retrospective assessment of sleep, including the sleep-interference visual analogue scale (from “strongly agree” to “strongly disagree”), the Pittsburgh Sleep Quality Index, the Pittsburgh Sleep Questionnaire, the Pre-Sleep Arousal Scale, the Epworth Sleepiness Scale, the Insomnia Severity Index, and the Sleep Disorders Questionnaire. A referral to a sleep medicine clinic or other provider specializing in sleep disorders (eg, psychologist) may be recommended for further assessment.

The diagnosis of sleep disorder is reserved for conditions identified with an objective sleep physiology study or polysomnographic evidence. A polygraph machine records change in bioelectric potentials using electrodes placed on the skin of the scalp and face. An EEG measuring brain waves, an electrooculogram (EOG) measuring eye movements, and an electromyogram (EMG) measuring muscle activity are recorded.34 Another innovative method for objective sleep monitoring—actigraphy—measures the sleeper’s activity during the night and day but is unable to distinguish between true sleep and moments of motionless wakefulness.34

What Does the Treatment of Insomnia Look Like?

Specific sleep disorders have specific treatments that can improve sleep for individuals with chronic pain. For example, continuous positive airway pressure (CPAP), use of a mouth appliance, decreased alcohol intake, and weight loss may be recommended for sleep apnea. A combination of adrenergic-blocking agents, levodopa/carbidopa combinations, and benzodiazepines have been used for RLS.34 However, the overall treatment approach to sleep in patients with chronic pain is based on optimizing pain control, identifying and treating psychiatric comorbidity, carefully investigating sleep patterns, and using sleep-specific pharmacotherapeutic and psychotherapeutic interventions to improve sleep.3

Medications often show little ongoing benefit for sleep and cause significant side effects.34 Epidemiologic studies show that 2.2% to 15% of US patients with insomnia report sedative-hypnotic use.35 Opioids have complex effects on sleep architecture and are known to increase nocturnal movements and arousals,36 cause daytime somnolence, and have a sedating effect,37 and patients may develop a tolerance to them over time.38 Traditional benzodiazepines should be discontinued if they are being used for sleep rather than anxiety because of their abuse potential and negative effect on sleep.3 If patients are being treated for comorbid depression, it is important to use sleep- friendly antidepressants (eg, trazodone and mirtazapine) rather than selective serotonin reuptake inhibitors.39 Pain experts also have found that newer anticonvulsants (eg, gabapentin) and atypical antipsychotics (eg, quetiapine) may be useful to improve sleep.3

When considering psychotherapeutic interventions to improve sleep, Cognitive Behavior Therapy for Insomnia (CBT-I) is widely regarded as one of the most effective treatments.40 Some of the CBT-I techniques—including sleep restriction, stimulus control, and relaxation—are independent treatments for insomnia that have strong research support.41

Sleep restriction therapy uses a form of systematic sleep limitation in which a sleep window is established and maintained to allow the body to relearn proper sleeping dynamics and increase sleep efficiency. Stimulus control therapy reduces the conditioned arousal individuals may experience when attempting to go to bed. Specifically, a set of instructions (going to bed only when sleepy; getting out of bed when unable to sleep; using the bed/bedroom only for sleep and sex; arising at the same time every morning; and avoiding naps) designed to reassociate the bed/bedroom with sleep and to re-establish a consistent sleep schedule are implemented.

Relaxation-based treatments teach formal exercises focused on reducing somatic tension (progressive muscle relaxation and autogenic training) or intrusive thoughts at bedtime (imagery training and meditation) and have been found to be equivocally effective. A 12-member National Institute of Health panel found general relaxation training helpful in chronic pain and insomnia.42

Biofeedback is yet another modality that has modest research support for the treatment of insomnia.41 Biofeedback is a training technique delivered by a trained mental health professional that conveys information about a patient’s bodily functions that are typically considered outside conscious control. When treating insomnia, biofeedback often is used in conjunction with relaxation training or other behavioral approaches. Biofeedback also has been shown to be effective for chronic pain management.43

In the next installment on the Mental Health A to Z Series, the author will discuss neurocognitive disorders and pain.

Last updated on: August 16, 2017
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A Plea for Proper Opioid Tapering

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