Chronic Insomnia and Pain
Chronic insomnia — a lack of restful, restorative sleep — is a co-morbid condition in Chronic Pain Syndrome, along with pain, fatigue, depression, anxiety,1 and sexual dysfunction.2 Ten to 15% of Americans have chronic insomnia and 50% never mention it to their physician. Thirty to 40% of adults have some symptoms of insomnia in any given year.3
While the incidence of insomnia is expected to be significantly higher in the patients with pain, such patients and their physicians often fail to address it directly. It is estimated that 60% to 80% of pain patients experience symptoms of insomnia—trouble falling asleep and/or staying asleep.
Patients typically do not characterize a sleeping problem as a health problem and so do not mention it during routine visits. Physicians, on the other hand, possibly untrained in treating insomnia, may choose to concentrate on conditions that are more tangible and measurable.
It is estimated that 75% of chronic insomnia can be improved by a caregiver that is well-informed and skilled.4 Patients typically experience more favorable outcomes with a treatment plan that is thorough and addresses all co-morbidities. The practitioner must be careful to treat underlying causes rather than just the symptoms. For example, a patient with trouble falling asleep who is anxious because of a work problem may be prescribed a sedative. The sedative will cause drowsiness and he may fall asleep, but the underlying anxiety has not been addressed. Another example: a man works fifteen hours a day and is fatigued. When questioned about sleep, he states he “sleeps like a log.” His fatigue is perceived as being caused only by work exhaustion, yet without further investigation, problems such as sleep apnea or depression related to dissatisfaction with his marriage could be missed, go unresolved — and thereby perpetuate fatigue and a sense of intractability.
Insomnia is defined as difficulty falling asleep, maintaining sleep, waking up too early, or non-refreshing sleep.5 Insomnia is a symptom — not a disease. Lack of sleep and the consequences are cumulative. Although chronic insomnia itself is not life threatening, it affects many aspects of normal functioning. The most prominent complaint with insomnia is fatigue. Lack of restful sleep is a major cause of fatigue. In addition to chronic pain, insomnia may also be caused by, or co-morbid with, a multitude of other non-pain related factors such as anxiety, panic, mania and depression,3,6 smoking, Chronic Obstructive Pulmonary Disease (COPD), Congestive Heart Failure (CHF), Gastro esophageal reflux disease (GERD), restless leg syndrome, periodic limb movement, alcohol and drug abuse, lack of physical activity, physical exhaustion, chronic pain, connective tissue diseases, benign prostatic hyperplasia (BPH), enuresis, sleep apnea and hormone imbalance (hot flashes). Insomnia can be both a risk factor for depressive disorders and/or a symptom of depression.6 The practitioner needs to ascertain whether there are multiple factors causing the insomnia aside from the pain/insomnia connection in order to select a suitable treatment.
Impediments to Restful Sleep
Chronic pain prevents the body from relaxing, which, in turn, blocks restful (delta wave) sleep. The lack of restful sleep amplifies a pain patient’s perception of pain. It is often hard to distinguish whether chronic pain has led to chronic insomnia or the other way around. With chronic pain, a pain medication or pain control may be more important than a sleep aid. While simply treating the pain with opiods may help some patients sleep due to improving comfort, others may sleep worse since opiods generally interfere with sleep architecture.
Certain other medications taken for physical or psychological disorders can also affect the body’s ability to achieve restful sleep. Such drugs may include beta-blockers, stimulating antidepressants, thyroid prescriptions, diuretics, calcium channel blockers, decongestants, steroids, and antiparkinsonian agents.7
Some simple sleep agents, such as Elavil, and hypnotics, such as Dalmane, actually decrease delta wave sleep and cause less restful/restorative sleep, resulting in increased fatigue.
Quality vs. Quantity of Sleep
The sleep process is classified into two phases — rapid eye movement (REM) and non-rapid eye movement (NREM). A typical night’s sleep alternates between multiple periods of REM and NREM sleep. During REM sleep, the blood flow of the body is concentrated to the brain and away from the muscles. This stage is associated with restoration of mental functioning. Lack of REM results in poor memory, decreased concentration, agitation, anxiety, and slow reaction times.8
Once the patterns of sleep are identified and the triggers for insomnia discovered, prioritize according to importance and tackle a couple at a time.
NREM sleep, also described as slow-wave sleep and delta wave sleep, is further separated into four stages. Stage one is a drowsy state. Stage two is a light sleep from which a person can be easily aroused. The third and fourth stages demonstrate delta waves on an EEG. This is the deepest level of sleep and is associated with physical restoration. Blood flow of the body is concentrated to the muscles and away from the brain. Lack of slow-wave sleep results in increased pain and malaise.8
The duration of each stage of sleep varies somewhat from person to person and night to night. Medications can increase the duration of stages one and two and prevent delta waves and REM sleep. Also a body can become accustomed to a long latent phase due to excessive worrying or watching television in bed. This extends stage one and two. This may develop into a repetitive pattern. With behavior modification, especially sleep modulation, the structure of sleep can be altered.
The amount of sleep actually needed varies from person to person. It is a myth that a person needs eight hours of sleep per night. Some people will go to the office feeling they must have insomnia because they only sleep six hours per night, yet they feel rested during the day. As long as the patient is refreshed upon awakening and does not easily fatigue during the day, the number of hours does not matter; this pattern does not qualify as insomnia. “Not sleeping very much is not considered insomnia unless it impairs your daytime functioning or physical or mental well being.”8
Finding the cause of insomnia makes treatment much easier than trying multiple medications and just waiting to see what works. A precise assessment often opens clues to the underlying cause. Physicians must move away from simply asking the patient: “Do you sleep ok?” First, patients want to please their caregiver, so they often answer with a simple “yes.” Second, a person can perceive that they went to bed, fell right to sleep, and woke eight hours later, but not feel rested in the morning. Patients will even insist they do not have insomnia. They state they sleep too much because they are so tired. These patients are sleeping enough, but are not experiencing restorative sleep.