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10 Articles in Volume 15, Issue #9
Differentiating Insomnia and Depression in Chronic Pain Therapy
Improving the Sex Lives of Patients With Chronic Pain
Incorporating Concierge Medicine into Pain Management
Interdisciplinary Rehabilitation: Information for Pain Practitioners
Latest Advances in the Diagnosis and Treatment of Polymyalgia Rheumatica
Letters to the Editors: Arachnoiditis, Pituitary Adenoma
Opioid Withdrawal: A New Look at Medication Options
Oral Opioids: Not for Everybody
Oxycodone Metabolism
Sexual Therapy for Patients with Chronic Pain

Differentiating Insomnia and Depression in Chronic Pain Therapy

Both insomnia and depression are considered comorbidities of chronic pain. However, insomnia should be considered its own entity, not just a symptom of depression or pain.

It is well established that chronic pain has a bidirectional relationship with insomnia—insomnia results in sleep deprivation, which leads to increased pain intensity the next day, which in turn makes it more difficult to have a good night’s sleep.1-4

Despite this relationship, insomnia typically is perceived as a secondary symptom of chronic pain. This may partially be due to how chronic pain patients express their sleep problems. It is common to hear a patient say: “I am in so much pain, so it is hard to sleep” or “Often, I wake up in the middle of the night because of the pain, and it’s hard to go back to sleep.” These complaints are legitimate.

The perception of insomnia as a secondary symptom also may be exacerbated by the fact that insomnia is a symptom of depression, which also is linked to chronic pain. Studies have shown that chronic pain is a strong predictor of the onset and maintenance of depression.5 Being constantly in pain can wear people down over time and affect mood.

Furthermore, chronic pain can limit activity, disturb sleep, and interfere with work performance, leading to depressed mood. Depression also can cause pain or exacerbate the pain experience.6 The resulting pain worsens depression, and depression intensifies the pain. Hence, a vicious cycle is created.

In terms of the insomnia-depression relationship, insomnia is listed as a symptom of depression. Depressed people may suffer from difficulty falling asleep (sleep-onset insomnia) or disturbed sleep throughout the night (sleep-maintenance insomnia). Patients with depressive symptoms often mention that they suffer from sleeplessness or that they find it hard to fall asleep.

However, although insomnia may be a predictor of depression, it is not always present with depression.7 Wilson et al found that insomnia is not always present as a symptom in chronic low back pain patients diagnosed with major depression.8 The same study demonstrated that not all chronic low back pain patients diagnosed with clinical insomnia suffer from major depression. In addition, studies evaluating a chronic musculoskeletal pain population have found that patients with severe insomnia do not always score high on depression measures and vice versa.9,10

This points to the conclusion that insomnia is a separate entity from depression in chronic pain. Rather, insomnia is comorbid with depression in chronic pain, not just a symptom of depression. This article will review insomnia and depression in the context of chronic pain, and discuss why insomnia and depression treatment in chronic pain needs to be differentiated.

Insomnia in Chronic Pain

Definition and Etiology

Over the years, insomnia has been cited as the most common sleep-related complaint.11,12 Although the term insomnia generally is used to describe difficulty initiating sleep, maintaining sleep, or having restorative sleep, there is a lack of consensus regarding what exactly constitutes insomnia, and there is no formal definition of insomnia.

There are several theories about the etiology of insomnia. One of them classifies insomnia as a disorder of hyperarousal.13 Hyperarousal may manifest as difficulty initiating and maintaining sleep at night, as well as creating a hypervigilant state during the day.14,15

Hyperarousal can be explained by physiologic and psychosocial models:

  • The physiologic model suggests that metabolic rate, heart rate variability, neuroendocrine measures, and functional neuroimaging indicate higher arousal in people with insomnia compared to controls.
  • The psychosocial model suggests that worry and rumination make it more difficult to initiate sleep and to return to sleep after awakening.16

Insomnia is exacerbated through conditioning.17 For example, an individual begins to associate the bedroom environment with difficulty falling asleep, which causes them to worry and be anxious, which then increases arousal. A daytime consequence of insomnia is sleepiness. To make up for this, individuals may nap during the day, which can interfere with their ability to fall asleep at night. An individual also may try to cure insomnia by going to bed too early. This behavior may be counterproductive and may heighten anxiety.

Prevalence and Consequences

Insomnia commonly is reported in chronic pain populations, with approximately 88% of chronic pain patients having some insomnia.18 Furthermore, Tang et al found that more than half of a chronic back pain population reported at least moderate insomnia.19

The presence of insomnia with chronic pain is associated with a variety of negative outcomes, such as anxiety, suicidal thoughts, more depressive symptoms, and limited daily functioning.9,20-24

Due to the high incidence of insomnia in chronic pain populations, insomnia often has been seen as a secondary symptom of chronic pain, with insomnia symptoms assumed to decrease as pain is managed. As a result, insomnia has not been set as a major target in the pain management regimen.

However, this view has gradually shifted, as new evidence has emerged pointing toward the bidirectional relationship between insomnia and chronic pain.1-4

Treatment

Insomnia treatment can be grouped into pharmacologic and psychosocial interventions. Pharmacologic treatment generally includes benzodiazepines, nonbenzodiazepines, melatonin receptor agonist, and antidepressants to manage the insomnia symptoms. Psychosocial interventions can be given to modify behavioral and environmental factors that perpetuate or exacerbate insomnia.

Pharmaceutical Treatment

Althought hypnotics are the most commonly prescribed medication, there are very few studies examining the use of hypnotics to treat insomnia in a chronic pain population; most of the literature is borrowed from studies conducted in primary insomnia populations.

Opioids typically are prescribed to lessen the pain, rather than to treat insomnia per se. It is expected that lessened pain will make it easier to fall asleep. However, prolonged opioid use is not advised, due to dependency issues and the potential for fracturing sleep architecture. Opioids block access to slow-wave sleep stages, thus hampering the ability to have restorative sleep.

Another class of medications used to treat insomnia in a chronic pain population is antidepressants, particularly the tricyclic antidepressants (TCAs; ie, trazodone). TCAs are preferred because they have sedating effects and thus facilitate sleep.25-27 TCAs also have another advantage: they can manage depression and serve as an adjuvant analgesic. However, dosages of TCAs like trazodone for sleep symptoms are often much lower than the dosages required to treat depression. When depression treatment is not needed, this helps reduce the “hangover” effect often caused by high-dose antidepressants. Regardless, in populations with chronic pain, insomnia, and depression, TCAs have the potential to address all 3 problems.

Psychosocial Intervention

The main purpose of psychosocial intervention is to modify factors that perpetuate or exacerbate insomnia, including cognition, emotion, and behavior. There are several therapies for insomnia, including sleep hygiene education, stimulus control, sleep restriction, relaxation, and cognitive therapy.

Sleep hygiene education provides patients with knowledge about habits that promote or interfere with sleep. People with insomnia are expected to modify their sleeping habits by adhering to sleep-promoting activities and avoiding sleep-interfering practices (Table 1).

Stimulus control therapy was developed through an operant conditioning model of the development and maintenance of insomnia. Insomnia is reinforced through inadequate stimulus control that may be due to the lack of discriminative stimuli or the presence of sleep-interfering stimuli.28 Stimulus control therapy requires people with insomnia to use the bedroom only for sleep and intercourse to reduce cues associated with arousal. This is expected to strengthen the bed and bedroom as cues for sleep and lessen their association with arousal as well as to help the patient develop a consistent sleep-wake schedule.

Sleep restriction therapy requires people with insomnia to restrict their time in bed. Sleep restriction therapy is based on the theory that disturbed sleep may benefit from restricted bedtime.29 Sleep restriction therapy starts with an initial 4 or 5 hours in bed. Then, the time spent in bed is increased until it reaches a normal amount of sleeping time (7-8 hours). The restrictions on time in bed are expected to break the insomnia cycle and restore homeostasis.30

Relaxation is another technique commonly used to treat insomnia.31 As discussed above, it is postulated that people with insomnia suffer from hyperarousal, including somatic arousal. Relaxation serves as a method to decrease the hyperarousal, thereby increasing the chance of people falling asleep. Among the existing relaxation techniques, progressive muscle relaxation has the most evidence for efficacy as an insomnia treatment.32 During progressive muscle relaxation, the patient lays down and slowly contracts and then relaxes the toes, feet, calves, knees, etc, all the way up to the shoulders, then ending with the face. A warm bath before bed and listening to soothing music or sounds also is recommended.

Cognitive therapy is another alternative to treat insomnia. Cognitive therapy for insomnia aims to modify dysfunctional beliefs and attitudes pertaining to sleep duration and the consequences of sleep that people with insomnia tend to have.33 To date, there is no randomized-controlled trial that examines cognitive therapy as a stand-alone therapy.33 It should be noted, though, that all of the above therapies are usually combined under the label of cognitive-behavioral therapy for insomnia (CBT-I). Research has shown that CBT-I has a high level of empirical support.32 Overall, based on 3 meta-analyses, CBT-I resulted in reliable changes in total sleep time, sleep onset latency, number of awakenings, duration of awakenings, and sleep quality ratings.22,34,35

Recently, sleep and pain experts have combined CBT for insomnia and pain, labeled as CBT-PI, with pain and insomnia management components. A sample program consists of 6 weekly 90-minute sessions: CBT-P involves pain education, physical activation, goal setting, relaxation, activity pacing, guided imagery, and cognitive restructuring. In CBT-PI, in addition to the standard components of CBT-P, an insomnia component (sleep hygiene education, stimulus control, sleep restriction, and daily sleep monitoring) is added.36 It was hoped that, by combining the 2 therapies, the management of insomnia in chronic pain would be more effective and efficient. Table 2, page 46, lists the components for pain management and insomnia management in CBT-PI.

Combining CBT for insomnia and pain has shown that insomnia is a different entity from pain; although the treatment is conducted within the pain management backdrop, insomnia needs to be a focus on its own. CBT-PI has been found to be superior to CBT-I for improving insomnia overall,36 as well as for improving measurements of waking-up-after-sleep-onset and depression. CBT-PI also more effectively improves insomnia than CBT-P,37 education only,37 and insomnia symptom monitoring38 approaches. However, neither CBT-PI nor CBT-I has been shown to result in significant improvement in pain severity.

In a study by Tang et al, chronic pain patients categorized as having moderate insomnia at the beginning of treatment were categorized as having subthreshold insomnia after receiving CBT-PI.38 Furthermore, participants receiving CBT-PI have reported greater reductions in insomnia severity than participants receiving only CBT-P or the education-only approach.37 CBT-PI significantly reduced pain interference,38 but not pain severity.37,38 This may be because CBT-PI assists in reducing pain catastrophizing and interference instead of reducing pain intensity. Although there are only a few studies examining CBT-PI, this intervention technique holds promise for the simultaneous management of insomnia and chronic pain.

Depression in Chronic Pain

Depression, or even depressive symptoms that do not reach threshold for diagnoses, is a significant problem for patients with chronic pain. In the general population of American adults, the prevalence of depression is approximately 8%.39 However, in patients with chronic pain, it is far more likely, with approximately 32% of chronic pain patients having major depressive disorder and an additional 36% demonstrating depressive symptoms.40 This relationship goes both ways: up to 60% of those with depression report having pain symptoms as well,6 and the likelihood of pain symptoms increases in patients with long-term disability.41

Patients with comorbid depressive symptoms and chronic pain differ from those with just depressive symptoms. They typically are more focused on negative health implications,42 may be less resilient to life changes,43,44 have more locations with pain and longer durations of pain, and use more pain medication than those without depressive symptoms.45 Patients with suicide ideation and chronic pain also differ from those with just chronic pain; they are more likely to be unemployed or disabled, have worse mental health, feel more hopeless, have greater illicit drug use,46 are more withdrawn, and have a history of abuse.47

Patients with comorbid depressive symptoms and chronic pain also may have somewhat different symptoms of depression. In pain patients, depressive symptoms can include feeling that everything is an effort, excessive worrying, and having disturbed sleep and low energy.48 Their depressive symptoms can influence pain intensity,49 as well as the degree to which pain interferes with daily function and mobility and the frequency of pain intrusion/breakthrough pain.50

In addition, expectations after an injury influence the severity of future symptoms.51 Therefore, a patient with depressive symptoms, who is demonstrating Beck’s “cognitive triad” of negative thinking about themselves, the future, and world around them, will most likely have a longer recovery time than someone who is more optimistic about the outcome of the injury. Rectifying these cognitive errors may be particularly difficult because coping with chronic pain takes additional resources.52

Patients also may feel stigmatized because of their chronic pain,53 which could add additional stress. Stressed patients may focus on the negative aspects of their injury only, overgeneralize their negative experiences to other areas of their lives, and feel personally responsible for negative occurrences, all of which can delay injury recovery.54 One recent study found that having depressive symptoms alone is enough to increase stress levels.55 The above explanation highlights how depression worsens chronic pain and, in turn, how chronic pain worsens depression. Thus, recognizing and treating depression in chronic pain patients is essential.

It is difficult to determine the exact etiology of depressive symptoms in chronic pain patients, and even more difficult to determine whether the depression or the chronic pain came first. It generally is accepted that chronic stress (such as the stress associated with an injury with a long recovery time) has an impact on mental well-being. Higher rates of psychopathology are found in chronic pain populations,56-58 and it has been shown that 39% of patients with chronic pain have their psychopathology before their pain condition. In addition, many patients have a history of mental health disorders in their family; negative coping patterns that they may have learned from family members can influence the progression of their injury.52

One study, however, determined through regression modeling that chronic pain was a more powerful predictor of depressive symptoms than depressive symptoms were of chronic pain.59 Those who had prior depression were older and had more chronic illnesses.60 Other theorized pathways for the development of depressive symptoms in the context of chronic pain include socioeconomic disadvantage as a child and maternal depression.61

Treating Pain and Depression

Although the treatment of pain and depression is beyond the scope of this article, there are many ways that patients can help themselves deal with depressive symptoms associated with chronic pain. Table 3 describes some self-directed approaches. For instance, natural lighting, especially in the winter, may help increase serotonin levels and improve mood. To increase light exposure, patients can walk briefly outside in the morning, sit next to a bright, sunny window, and use full-spectrum light bulbs indoors. Increasing activity levels is another option. Although often difficult to initiate, physical exercise, particularly aerobic exercise, is one of the most effective treatments for depression. It also is beneficial to avoid other chemical depressants, such as alcohol,62 and to set up a routine, so that it becomes habit to get things done rather than to become inactive due to depressive symptoms.

When patients are setting up a routine, they should be advised to make small changes and build slowly, so that things do not become overwhelming and trigger even more depressive symptoms. Patients also can be encouraged to set up a “wellness toolbox,” where they can keep a list of activities that help them feel safe, happy, and healthy. Activities include hobbies, positive people to talk with, favorite movies, books, or shows, resources for emergencies, and anything else the patient feels is helpful.63 Guided imagery also has been shown to be effective to decrease both pain levels and depressive symptoms64 and can be added to the toolbox.

Aside from self-help, there are a wide variety of other treatments available for depression and chronic pain. Typically, the first treatment used for musculoskeletal injury is primary rehabilitation, which helps control pain and encourages typical healing. Over-the-counter analgesics, muscle relaxants/opioids in rare cases, and physical agents such as ultrasound, heat, cold, and electrical stimulation all are examples of primary rehabilitation treatment.

If patients have a particularly severe injury or do not respond well to primary rehabilitation, then secondary rehabilitation is required. The goals of secondary rehabilitation include: prevention of physical deconditioning, medication habituation, and adverse psychosocial reactions. In addition, secondary rehabilitation aims to increase mobilization and strength to restore the injured area to function.

If secondary rehabilitation is unsuccessful, then tertiary rehabilitation takes place.65 The most effective tertiary intervention is interdisciplinary treatment following the biopsychosocial model, which treats the biological, psychological, and social components of injury.66,67 One specific interdisciplinary program is functional restoration, which focuses on return to function rather than just pain reduction. Functional restoration consists of medically supervised, quantitatively-directed exercise progression combined with a multimodal disability management program (MDMP).

The components of MDMP include CBT, stress management/biofeedback training, education, and vocational reintegration.68,69 CBT and vocational reintegration should address any secondary gain factors involved. The stress management component of CBT can include many different factors. For example, goal-setting and helping patients develop positive social support and a perception of control can be helpful for patients struggling with depressive symptoms. Medication management for depression also can be used, with antidepressants prescribed most often.70

Differentiating Treatment for Insomnia and Depression in Chronic Pain

As noted, one symptom of depression is insomnia. However, that does not mean that insomnia is a secondary symptom of depression in patients with chronic pain. Insomnia can occur without major depression in patients with chronic musculoskeletal pain.8 Patients with chronic pain and concurrent major depression and insomnia “report the highest levels of pain-related impairment, but insomnia in the absence of major depression is also associated with increased pain and distress,” noted Wilson et al.8 In a chronic musculoskeletal disorder population, patients classified as having moderate and severe clinical insomnia do not always score high on depression measures.9 These findings further support the notion that insomnia is not a secondary symptom of depression. Thus, it is imperative to differentiate the treatment of insomnia from that of depression treatment for patients with chronic pain.

This differentiation also is important because some characteristics of insomnia differ from depression characteristics. Insomnia is a disorder of hyperarosual,13 manifested in difficulty falling and/or maintaining sleep, whereas depression is a disorder of low mood that may manifest as either insomnia or hypersomnia, as well as a variety of other non-sleep related symptoms. Insomnia treatment focuses on normalizing sleeping patterns, reducing anxiety, and modifying sleep-maladaptive thoughts. Depression treatment aims to elevate mood and modify the cognitive triad of negative thinking that influences mood. Out of necessity, the treatment focus for insomnia and depression must differ. Studies evaluating the efficacy of insomnia treatment in chronic pain populations have found that sleep improvement is not always followed by depressive symptom improvement.71,72 These findings further support the importance of differentiation.

Although differentiation is necessary, some intervention techniques for insomnia and depression, such as relaxation, can treat both disorders at the same time. It is common for chronic pain patients to be tense because they have been dealing with pain for a long time. They also may be anxious and distressed over their condition and its associated social, physical, and occupational consequences. Thus, relaxation can help reduce their tension. Relaxation also can facilitate sleep. Furthermore, chronic pain patients suffering from depression experience emotional distress. Thus, teaching them relaxation techniques can help reduce tension and manage such distress. Some intervention techniques, such as physical activation and setting up a routine, are used to treat depression and chronic pain but can also have an impact on insomnia. Engaging in physical activities and having a routine gives depressed patients a sense of purpose. Furthermore, physical activities also facilitate physical reconditioning, which is important for chronic pain patients. By creating a routine, chronic pain patients with insomnia also will have a schedule that may help normalize their sleep-wake cycle.

Summary

It is essential to differentiate the treatment for insomnia and depression in patients with chronic pain. The differentiation is necessary because although insomnia and depression are comorbid, each should be considered a separate entity. Although treatment differentiation is necessary, some techniques can be given concurrently. Furthermore, intervention given to treat one problem can have a desirable domino effect on comorbidities. Understanding insomnia and depression as comorbidities of chronic pain will help practitioners deliver more effective treatment to their patients.

Last updated on: November 10, 2015
Continue Reading:
Chronic Pain and Depression: Sorting Out Types of Mood Disorders

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