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* From the Departments of Medicine (Dr. Summers) and Behavioral Science (Drs. Crisostomo and Stepanski), Rush University Medical Center, Chicago, IL.
Correspondence to: Michael O. Summers, MD, Rush University Medical Center, Sleep Disorders Center-JRB-6S, 710 S Pauline St, Chicago, IL 60612; e-mail: michael_summers{at}rush.edu
Abstract
Sleep/wake complaints, and specifically insomnia, are some of the more common problems encountered in the outpatient setting. Despite its prevalence, few clinicians are experts at diagnosing and treating this entity. Additionally, diagnosis and treatment of insomnia is a time-intensive process (often the initial interview takes at least 1 h, depending on the complexity of the insomnia). With a conservative estimate of the annual cost of insomnia between $92.5 and $107.5 billion dollars, it is becoming clear that insomnia has significant medical and public health implications. A problem that has hampered insomnia research is the lack of a standard definition of insomnia for use in research, as well as guidelines for assessment. In recent years, there have been important advances in the classification, evaluation, and treatment of insomnia with efforts to establish greater consensus in how to define and measure insomnia. Cognitive behavioral and pharmacologic therapies have been shown to be effective treatment approaches. Insomnia is a complex entity, often multifactorial in its etiology; and as research and clinical guidelines are established and validated (leading to better data interpretation), continued enhancement of our understanding of this disorder is expected.
Key Words: chronic insomnia dims insomnia primary insomnia review secondary insomnia sleeplessness
Insomnia is defined as a complaint of difficulty initiating sleep, difficulty maintaining sleep, waking up too early, or sleep that is chronically nonrestorative or poor in quality.1 Approximately one third of the US adult population reports difficulty sleeping, and 10 to 15% have the clinical disorder of insomnia.2 Over the years, there have been considerable scientific advances in both the understanding and treatments for insomnia. Despite these advances, insomnia continues to be inadequately identified and treated.
The inadequate identification and treatment of insomnia has significant medical and public health implications. Chronic insomnia results in impaired occupational performance and diminished quality of life,34 as well as higher health-care usage and costs.5 In 1994, Stoller6 placed a conservative estimate of the annual cost of insomnia (both direct and indirect costs) between $92.5 and $107.5 billion.
Insomnia has become a major health-care concern over recent years, as evidenced by the increased monies spent on both clinical and pharmaceutical research. As awareness of insomnia by the public continues to increase, it is important that the clinician who sees patients with sleep/wake complaints is adept in the identification, evaluation, and treatment of insomnia. This article aims to provide the reader with the most recent developments in the classification of insomnia, its evaluation, and treatment strategies.
Classification
The importance of the use of a consistent diagnosis and classification system is often underappreciated. In the clinical realm, it ensures effective communication with colleagues, resulting in improved patient care. In the research arena, consistency plays a major role toward a better understanding of the pathophysiology and ultimate treatment of a disorder. Diagnosis and classification systems are also playing an ever-increasing role in the issue of medical reimbursement. As managed care becomes more pervasive, it is the patients specific diagnosis that ultimately determines the approval of reimbursement for a treatment plan.
A fundamental obstacle that has made interpretation of insomnia research particularly problematic is the lack of operationally defined inclusion and exclusion criteria that standardize the definitions of insomnia. Having research diagnostic criteria (RDC) has been shown to significantly improve the diagnostic reliability among clinicians and researchers.7 In August 1999, the American Academy of Sleep Medicine (AASM), recognizing the importance of RDC, commissioned the development of RDC for insomnia. The 5 years of work culminated in the publication of their results in 2004.8
The publication of the Diagnostic Classification of Sleep and Arousal Disorders9 by the Association of Sleep Disorders in 1979 heralded the emergence of the discipline of sleep medicine. This was followed by the International Classification of Sleep Disorders (ICSD), published in 1990. In 2005, the second edition of the ICSD (ICSD-2) was published.1 It is this classification system that will be referred to throughout this article.
It has been shown that the ICSD system, while used frequently (as use was required for center accreditation by the AASM), was not the preferred classification system by clinicians.10 A more intuitive symptom-based approach was preferred, and it is this type of approach that is employed in the ICSD-2.
The ICSD-2 system for insomnia bears resemblance, in many aspects, to the original 1979 classification system.9 The ICSD-2 is a modified version of the original classification system, which results in fewer overall categories, and a grouping of the various psychiatric disorders of the original ICSD (eg, mood disorders, post traumatic stress disorder) into a single category "insomnia due to mental disorder." The term paradoxical insomnia has also replaced the older term sleep state misperception. This term refers to the paradoxical relation between the objective and subjective assessments of sleep in these patients. They report sleeping little or not at all despite having normal sleep established by traditional EEG measures. The term sleep state misperception was believed to be inadequate, in that these patients may well have some difficulty with quality of sleep not detected by use of surface electrodes in quantifying sleep depth.
So what is the difference between the RDC and the ICSD-2? The RDC is a set of criteria meant to be used to aid researchers in order to establish consistency in study design and data interpretation. The ICSD-2 is a set of diagnostic criteria to aid the clinician in establishing a clinical diagnosis for a patient. The definition of insomnia and its subtypes are consistent in both publications, and are done so intentionally.
The general criteria for the diagnosis of insomnia are displayed in Table 1 . It is necessary that a patient fulfill these criteria before a diagnosis of insomnia can be made. Table 2 lists the classifications of insomnia per the ICSD-2, with the three of the most common types of insomnia (in no specific order) encountered in a clinical sleep center, which will be discussed further in this section. The reader is encouraged to reference the ICSD-2 manual, as a thorough discussion of all aspects of the classification system is beyond the scope of this article.
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Often referred to as acute insomnia, adjustment insomnia has a 1-year prevalence among adults of 15 to 20%. It is more common in women than men, and in older adults rather than younger adults and children.
The essential feature to a diagnosis of adjustment insomnia is the presence of an identifiable stressor. It is typically of short duration (days to weeks), lasts no more than 3 months, and is expected to resolve with either adaptation to or resolution of the stressor. Should the patients symptoms persist > 3 months, an alternate diagnosis of one of the more chronic insomnias should be considered.
Often the patient will complain of inability to get to sleep (prolonged sleep latency), an increase in both frequency and duration of nighttime awakenings, and decreased total sleep time. There exists the potential for abuse of illicit drugs, medications (both prescription and over the counter), and alcohol in these patients in an effort to try to obtain sleep. Behaviors may also develop that over time may lead to more persistent forms of insomnia.
Psychophysiologic Insomnia
Psychophysiologic insomnia is also referred to as learned or conditioned insomnia. A patient with psychophysiologic insomnia is often overfocused on the problem of sleep and experiences increased arousal at bedtime when preparing to sleep. This is differentiated from a generalized anxiety disorder, in that the overconcern is focused solely on sleep, while an individual with an anxiety disorder would typically have many other areas of impaired function. The onset typically is in young adulthood and can persist for decades. Psychophysiologic insomnia shares many symptoms with adjustment insomnia, and distinguishes itself based on its longer duration and absence of an identifiable precipitant (Table 3 ).
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This form of insomnia is reported to be found in 1 to 2% of the general population. Of all patients presenting to sleep centers for evaluation of insomnia, psychophysiologic insomnia accounts for 12 to 15% of the diagnoses.11 If left untreated, the patient typically has symptoms that will persist for decades and gradually worsen as a cycle of fitful sleep, daytime irritability, and poor concentration develop. The first episode or recurrence of major depression and excessive use of sleep aids are potential complications of persistent psychophysiologic insomnia.
Insomnia Due to a Mental Disorder
Insomnia due to a mental disorder is the most common diagnosis among individuals presenting to a sleep center for evaluation and treatment of chronic insomnia11 (Table 4 ). Mood disorders such as major depressive disorder, dysthymic disorder, bipolar disorder, and cyclothymic disorder may all underlie this type of insomnia.1 Most anxiety disorders also may give rise to this condition. It is a distinct complaint or focus of treatment, separate from their mental disorder. When further history is obtained it is often noted that the severity of the patients insomnia correlates with the course of their underlying mental disorder.
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Evaluation of Insomnia
Previous articles1213 have given guidelines on the assessment of insomnia, and a brief review will be provided as well as recent developments. As previously mentioned, the lack of standardized criteria pose a significant obstacle to the assessment, treatment, and continued research in insomnia. In recognition of this problem, the research diagnostic criteria for insomnia was formulated by the AASM work group,8 and a standard research assessment of insomnia was proposed by Buysse.14
The latter work emphasizes that the standards for insomnia assessment were recommended specifically for research studies, although it is recognized that clinicians may find that the recommendations could facilitate characterization of their patients as well as treatment outcomes. Given the multidimensional characteristics of insomnia, a thorough understanding of insomnia would necessitate the assessment of multiple components such as evaluation for other sleep disorders or comorbid conditions, quantitative and qualitative sleep measures, and daytime function and consequences of insomnia.121415
Guidelines exist for the use of polysomnography in insomnia16 as well as practice parameters for the evaluation of chronic insomnia.13 As pointed out in the latter article,13 there are no data available that empirically demonstrate which assessment tools should be included in a systematic evaluation with respect to the validity of the diagnosis and treatment outcomes. Martin and Ancoli-Israel17 in 2002 noted in their review of 54 nonpharmacologic intervention studies of insomnia that 76% of the studies used multiple assessment modalities. To date, there is no agreement on the optimum combination of the various evaluation measures.17
Keeping in mind the proposed recommendations for standard research assessment of insomnia by Buysse,14 and the complex multidimensionality of insomnia, we recommend that a thorough evaluation would involve at the basic level a comprehensive history and physical examination, with sleep logs/diaries and structured questionnaire(s). This could be further supplemented by specific structured interviews and questionnaire(s), polysomnography, actigraphy, and other evaluation tools as directed by the initial evaluation and history.
Sleep History
As with all disciplines of clinical medicine, the most fundamental aspect of any patient evaluation is obtaining a detailed medical history. A thorough comprehensive history cannot be overemphasized. In a review of the nonpharmacologic interventions used in insomnia, the face-to-face interview was the most common (80% of 54 studies) sleep assessment tool utilized.17 It is the history that will allow the clinician to discover concomitant medical and psychiatric disorders that may be contributing to their insomnia. Other primary sleep disorders may also be present (eg, obstructive sleep apnea or restless legs syndrome) that may be identified during the interview process. A review of all medications the patient is currently receiving (as well as any past medications used to facilitate sleep) should be performed. The sleep history should include the components outlined in Table 5 . A list of medications reported to contribute to insomnia is in Table 6 .
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The initial sleep history may provide a take-off point for additional evaluations such as structured clinical interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition18 for psychiatric disorders along with the psychiatric history. Global sleep and insomnia symptoms can be assessed with the Pittsburgh sleep quality index and the insomnia severity index. The former was not specifically designed for insomnia but has demonstrated validity and reliability in assessing sleep quality over a 1-month interval.19 The latter measures the patients perception of insomnia, and the subjective symptoms and consequences, along with the degree of impairment or emotional distress associated with the insomnia. Therefore, this metric captures a significant aspect of the diagnostic criteria of insomnia. It has been demonstrated to be a valid and reliable instrument to assess perceived insomnia severity in young and older patient samples of primary and secondary insomniacs.20 A review by Moul et al21 provides a list of currently available questionnaires to assist clinicians and investigators involved in insomnia.
Sleep Logs and Diaries
Sleep logs are often used in the preliminary evaluation of patients presenting for a sleep disorder. Twenty studies were reviewed by Sateia and others,12 and they noted that the studies report modest-to-poor correlations between subjective reports and objective findings, with a tendency to underestimate total sleep time and overestimate sleep latency. Two of the 20 studies showed significant discrimination between insomniacs and normal sleepers based on the sleep logs. The authors12 stated that sleep logs may be better indicators of patient perception of sleep disturbance rather than quantitative sleep abnormalities. However these perceptions may represent a valid index of insomnia as objective measures and may be more accurate than any single, global estimate of sleep pattern.
Polysomnography
The Standard of Practice Committee of the AASM in their report16 on practice parameters for the evaluation of chronic insomnia stated that polysomnography is not indicated for the routine evaluation of transient insomnia, chronic insomnia, or insomnia associated with sleep disorders. However polysomnography may be indicated if there is valid indication and clear rationale, based on specific elements of the history to support use of polysomnography, such as when there is a suspicion for sleep-related breathing disorder or periodic limb movement disorder. It may be indicated if initial diagnosis is uncertain, treatment fails, or precipitous arousals occur with violent or injurious behavior.
Actigraphy
The actigraph is a watch-sized motion sensor that the patient wears on the nondominant wrist. Most actigraphs can record rest/activity data for
2 weeks continuously. Some of the more advanced actigraphs may be able to collect information such as ambient light exposure or patient self-report data. When the patient is quiet and no movement is recorded, the patient is presumed to be sleeping. Obviously there are limitations to the accuracy of this data (eg, was the patient really sleeping? was the patient just lying there ruminating? or perhaps they had taken the watch off). It is for this reason that coupling the actigraph data with a sleep diary is very important. When the patient returns to the clinic, the device is connected to a computer that downloads the information from the actigraph, runs an algorithm to perform sleep and wake estimation, and presents the data in numerical and graphical formats.
The use of actigraphy has been reviewed in 2003 by the Standard and Practice Committee of the AASM, and the summary conclusions state the use of actigraphy is not indicated in the routine diagnosis, assessment, or management of any of the sleep disorders.22 However, actigraphy may serve as a useful adjunct to the assessment of other disorders such as insomnia, circadian-rhythm disorders, or disorders of sleepiness.
Actigraphy can supplement the initial patient evaluation consisting of history, physical examination, and sleep diary to provide additional information of sequential daily rest/activity patterns. Actigraph information can help diagnose, document severity, and guide the proper treatment and monitor compliance to treatment for insomnia. It may also serve a role in patients in whom an accurate history cannot be or is difficult to obtain.
With its ability to assess sleep/wake patterns, actigraphy can be useful in the evaluation of circadian rhythm patterns such as delayed sleep phase syndrome (the reader is encouraged to review the article by Wyatt23 for a more thorough understanding of delayed sleep phase syndrome) or advanced sleep phase syndrome. Actigraphy may be useful in characterizing and monitoring circadian rhythm patterns or disturbances in the following special populations: elderly and nursing home patients with and without dementia, newborns, infants, children, adolescents, hypertensive individuals, depressed or schizophrenic patients, and individuals in inaccessible situations, such as space flight. Actigraphy can also be helpful as an outcome measure to measure effects of treatments interventional trials in patients with obstructive sleep apnea, insomnia,15 periodic limb movement disorder, and restless legs syndrome. Actigraphy has also been found useful in outcome studies of healthy adults, patients with certain medical and psychiatric conditions, and children and the elderly. Vallieres and Morin15 demonstrated actigraphy to provide a more accurate data than the sleep diary when compared to polysomnography and that it was sensitive to the effects of treatment, suggesting that actigraphy may prove to be a useful device for treatment evaluation and may complement the use of sleep diaries.
Having an appreciation for the patients underlying predisposition to insomnia, as well as discovering the precipitating and perpetuating factors24 contributing to the insomnia, the clinician can target therapy accordingly. As has been mentioned, while progress is being made, we are hindered by the lack of clear assessment guidelines that have been systematically validated. Future research in these areas is needed.
Cognitive and Behavioral Treatment
Sleep Hygiene
Up to 30% of patients presenting to a sleep center for treatment of insomnia have inadequate sleep hygiene as either a primary or secondary diagnosis (Table 7
). Sleep hygiene addresses conditions and practices that promote continuous and effective sleep. Evaluation of a patients sleep hygiene is recommended in all patients who present with insomnia, as patients tend to adapt behaviors that foster poor sleep quality, resulting in perpetual sleep complaints. Only with identification of these behaviors can the sleep clinician adequately treat sleep hygiene issues.
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Sleep hygiene rules were first proposed by Hauri25 and included a wide range of recommendations to address presumed behavioral and cognitive contributions to insomnia (Table 8 ). There are now many versions of sleep hygiene rules, and they are uniformly recommended in the treatment of insomnia. Most lists of sleep hygiene include recommendations to limit use of caffeine and alcohol, engage in exercise, and to make certain that the sleep environment is sufficiently dark and quiet to be conducive to sleep. Hauris original list also included recommendations to limit time in bed and go to bed only when sleepy. These recommendations overlap with sleep restriction therapy and stimulus control therapy as described below.
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Relaxation Therapy
The use of relaxation therapy is based on the theory that hyperarousal causes insomnia, and that if patients learn techniques to reduce arousal this will lead to improved sleep. The term relaxation therapy is a generic term that encompasses many different approaches to accomplish the same general goal. These approaches differ somewhat in terms of how much emphasis is placed on reducing cognitive arousal vs somatic arousal. For example, progressive muscle relaxation (PMR) is more focused on somatic arousal, while guided imagery is more focused on cognitive arousal.
PMR
PMR has been used in the treatment of insomnia for many years. These techniques were developed by Edmund Jacobsen27 in the 1930s, and he applied them to the treatment of insomnia in 1938. In PMR, the patient is taught to systematically relax each part of the body until the entire body is relaxed.28 The usual procedure for this consists of first tensing up the muscles in that body part, maintaining the tension for a few moments, and then releasing the tension. Many studies2930 of the efficacy of these techniques in the treatment of insomnia have been conducted with good results.
Biofeedback
Biofeedback using both electromyography and EEG has been used in the treatment of insomnia.31 Biofeedback teaches relaxation by providing a signal to the patient that reflects the tension level, either based on electromyographic activity or EEG activity. The theory underlying this treatment approach is that the patient will better learn how to produce relaxation when given immediate feedback regarding increases or decreases in tension that result from attempts to control this tension.
Use of biofeedback to treat insomnia is not common, probably because of the duration and intensity of this treatment. Patients may require 30 to 90 individual biofeedback sessions to successfully master relaxation sufficiently to improve sleep.
Guided Imagery
Guided imagery is a form of meditation and consists of having the patient visualize a specific scene that is associated with a calm and relaxed state. Typically, the patient first engages in a simple relaxation procedure, such as deep breathing, to become relaxed. Then a specific scene is visualized to deepen the relaxation. Examples of relaxing scenes include lying on a beach, sitting in front of a fire in a cabin in winter, or soaking in a hot bath. Once the patient has practiced this relaxation exercise sufficiently, the relaxation becomes paired with the visual imagery. Then the patient can induce a relaxed state quickly by closing the eyes and focusing on the visual imagery. Theoretically, this approach may be more useful for patients who have cognitive arousal as their primary source of tension, since the imagery provides a distraction from their customary worries and fears.
Stimulus Control Therapy
Stimulus control therapy (SCT) is a specific type of cognitive behavioral therapy that is based on the assumption that insomnia is due to increased tension and arousal that occurs as a conditioned response to the stimulus of the sleep environment. Spending time in bed, wide awake, strengthens the association between wakefulness and the bedroom, leading to continued insomnia. Therefore, the primary goal is to have the patient in bed only when drowsy or asleep. SCT is aimed at breaking the association between wakefulness and the sleep environment.31 There are just six rules for this treatment, as shown in Table 9
.
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Sleep Restriction Therapy
Sleep restriction therapy is a behavioral treatment based on manipulating time in bed according to systematic rules33 (Table 10
). Bedtime is delayed and total time in bed is reduced in order to increase homeostatic sleep drive and thereby improve sleep propensity. As sleep improves, patients are allowed to advance their bedtime to increase time in bed as long as they can continue to fall asleep quickly and sleep most of the night. One drawback to this treatment approach is that patients have been shown to be sleepier during the day during the initial phases of treatment. Additionally, many patients are reluctant to reduce their time in bed, since they perceive that this also reduces their opportunity to obtain adequate sleep time. Adherence to the treatment may be reduced for these reasons.
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Cognitive restructuring is a type of cognitive therapy that modifies dysfunctional cognitive processes. This is accomplished by first systematically identifying cognitive problems. Then the misattribution, exaggeration, unrealistic expectation, or other inappropriate cognition is challenged and replaced with a more rational interpretation of the situation.
Cognitive and Behavioral Therapy Programs
Programs that combine several of the treatments described above have been designed for use with patients with insomnia.343536 These programs are conducted over a period of weeks and may be used to treat patients with insomnia individually or in a group format. Each week, a new treatment is introduced and the treatments from prior weeks are reviewed. A typical program combines sleep hygiene, stimulus-control therapy, sleep restriction therapy, relaxation training, and cognitive therapy into an 8-week program.
Cognitive and behavioral treatment programs have been shown to be as effective as pharmacologic treatment, with better maintenance of benefit at long-term follow-up.35 This treatment requires increased motivation on the part of the patient and also requires more clinician time to implement.
Advances in Pharmacologic Treatment of Insomnia
The most commonly used compounds for the treatment of insomnia are benzodiazepines, and nonbenzodiazepines that are
-aminobutyric acid-ergic. These compounds have superior safety and efficacy profiles compared to prior classes of hypnotic medications (eg, barbiturates, ethchlorvynol).
A critical aspect of selecting an appropriate hypnotic compound for a given patient is the consideration of the duration of action (Table 11 ). Long-acting benzodiazepine medications (eg, flurazepam, clorazepate) lead to significant daytime sedation. Significant daytime sleepiness has been shown with objective measures such as the multiple sleep latency test and psychomotor performance testing.37 Residual sedation is usually an undesirable side effect in the treatment of insomnia, and development of new compounds has focused on short-acting medications. However, if a medication is too short acting, it is useful for decreasing sleep onset latency but does not improve sleep maintenance38 (eg, zaleplon). New hypnotic medications have aimed to provide sedation for about 7 h (eg, eszopiclone, zolpidem continuous release). One advance is that a clinical trial39 found continued efficacy over a 6-month period. Previously, trials of long-term administration of a hypnotic tended to be 6 weeks in duration. Demonstrating the efficacy of hypnotic medication over longer time intervals is important given that often patients with chronic insomnia will require longer-term treatment.
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Conclusion
Sleep/wake complaints, and specifically insomnia, are some of the more common problems encountered in the outpatient setting. Despite its prevalence, few clinicians feel comfortable diagnosing and treating this entity. Adding to this difficulty is the fact that diagnosis and treatment of insomnia is a time-intensive process (often the initial interview takes at least 1 h, depending on the complexity of the insomnia). Insomnia is a complex entity, often multifactorial in its etiology; and as research and clinical guidelines are established and validated (leading to better data interpretation), continued enhancement of our understanding of this disorder is expected.
Footnotes
Abbreviations: AASM = American Academy of Sleep Medicine; ICSD = International Classification of Sleep Disorders; ICSD-2 = International Classification of Sleep Disorders, Second Edition; PMR = progressive muscle relaxation; RDC = research diagnostic criteria Learning Objectives: 1. Summarize the advances in the diagnosis, classification and evaluation of insomnia. 2. Discuss the current treatment options available for insomnia with emphasis on the effectiveness of Cognitive Behavioral Therapy and Pharmacotherapy.
Dr. Summers has conducted research for GlaxoSmithKline. Dr. Crisostomo has conducted research for Organon. Dr. Stepanski has conducted research for Sanofi-Aventis.
Received for publication January 27, 2006. Accepted for publication April 4, 2006.
References
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