Introduction: Although nearly
15% of adults experience chronic primary insomnia, few have access to effective
behavioral treatments. The purpose of this study was to conduct a pilot
investigation of a handheld computer designed to treat primary insomnia
symptoms. The device, developed from NIH funding, uses the principles of sleep
monitoring, sleep restriction, and behavioral prompting to modify sleep
Method: We conducted a 3-week pilot investigation of the device.
Participants were screened for primary insomnia via the Insomnia History
Interview. Thirty-one participants with DSM-IV primary insomnia were enrolled.
Baseline measures included the Insomnia Severity Index (ISI) and electronic
sleep diaries. Diaries were recorded for one week during baseline and at again
at post-treatment. Paired sample t-tests were conducted to examine
changes in sleep and insomnia severity from baseline to end of treatment.
Results: The sample was 80% female, 80% White and 77% married.
Participants had a mean score of 18 (SD 3.6) in the ISI. Post-treatment
visit revealed significant changes in insomnia symptoms from baseline: ISI
severity dropped from 18 to 9.8 (p < .001), sleep onset latency,
wakefulness after sleep onset, early awakenings, and number of arousals all
decreased significantly from baseline to post-test (all p's < .01).
Sleep efficiency was significantly improved from baseline (p < .01).
Conclusions: Data from this pilot study indicate that the computerized
treatment was well tolerated and associated with improvements in sleep and
amelioration of insomnia symptoms. Qualitative and other data will be presented
and implications of the study discussed.
Conference Statement on Manifestations
and Management of Chronic Insomnia in Adults
National Institutes of Health
State-of-the-Science Conference Statement
June 13-15, 2005
August 18, 2005
NIH Consensus and State-of-the-Science statements are prepared by
independent panels of health professionals and public representatives on the
basis of (1) the results of a systematic literature review prepared under
contract with the Agency for Healthcare Research and Quality (AHRQ), (2)
presentations by investigators working in areas relevant to the conference
questions during a 2-day public session, (3) questions and statements from
conference attendees during open discussion periods that are part of the public
session, and (4) closed deliberations by the panel during the remainder of the
second day and morning of the third. This statement is an independent report of
the panel and is not a policy statement of the NIH or the Federal Government.
The statement reflects the panel's assessment of medical knowledge available
at the time the statement was written. Thus, it provides a "snapshot in time"
of the state of knowledge on the conference topic. When reading the statement,
keep in mind that new knowledge is inevitably accumulating through medical
Insomnia is the most common sleep complaint across all stages of adulthood, and
for millions, the problem is chronic. Insomnia often is comorbid with other
disorders, particularly depression, as well as some cardiovascular, pulmonary,
and gastrointestinal disorders. In the absence of comorbid conditions, insomnia
is thought to be a primary disorder in itself. Whether it is the primary
disorder or secondary to some other condition, chronic insomnia is often
associated with a wide range of adverse conditions, including mood
disturbances, difficulties with concentration, and memory. Whether insomnia is
the cause or result of associated problems is not always easily determined, but
is critical to treatment strategies for individual patients.
A variety of behavioral and pharmacological approaches show promise for managing
chronic insomnia symptoms. However, there has been limited guidance for
clinicians in choosing the best treatment for chronic insomnia due to the
paucity of randomized clinical trials (RCTs) for many widely used treatments.
Available treatments include an array of behavioral or nonpharmacologic
interventions; hypnotic medications; and antidepressant, antipsychotic, or
As pointed out in the recent 2003 National Sleep Disorders Research Plan,
published by the National Center on Sleep Disorders Research at the National
Institutes of Health (NIH), there is great need for additional research to
better define the nature of chronic insomnia and ways to characterize its
detailed expression in diverse patients. Additional systematic research is also
greatly needed to provide a more thorough database from which clinicians and
patients can make more informed choices about treatment options.
To address these needs, the National Institute of Mental Health and the Office
of Medical Applications of Research of the NIH sponsored a State-of-the-Science
Conference on the Manifestations and Management of Chronic Insomnia in Adults
on June 13–15, 2005, in Bethesda, MD. During the first 2 days of the
conference, experts presented the latest scientific knowledge about chronic
insomnia and available treatments. After weighing all of the scientific
evidence, an independent panel prepared and presented the following
state-of-the-science statement. The panel was charged with answering five
How is chronic insomnia defined, diagnosed, and classified, and what is known
about its etiology?
What are the prevalence, natural history, incidence, and risk factors for
What are the consequences, morbidities, comorbidities, and public health burden
associated with chronic insomnia?
What treatments are used for the management of chronic insomnia, and what is
the evidence regarding their safety, efficacy, and effectiveness?
What are important future directions for insomnia-related research?
The conference was intended for health care professionals, researchers, patients
and their families, and members of the public interested in the nature of and
available treatments for chronic insomnia. The conference included formal
expert presentations focusing on the individual conference questions and oral
and written input from professionals and members of the lay public. In
addition, the independent panel benefited greatly from a comprehensive
systematic literature review, prepared by the University of Alberta
Evidence-based Practice Center.
1. How is chronic insomnia defined, diagnosed, and classified, and what is known
about its etiology?
Insomnia may be defined as complaints of disturbed sleep in the presence of
adequate opportunity and circumstance for sleep. The disturbance may consist of
one or more of three features: (1) difficulty in initiating sleep; (2)
difficulty in maintaining sleep; or (3) waking up too early. A fourth
characteristic, nonrestorative or poor-quality sleep, has frequently been
included in the definition, although there is controversy as to whether
individuals with this complaint share similar pathophysiologic mechanisms with
Chronic insomnia should be distinguished from acute insomnia, which may occur in
anyone at one time or another (e.g., the night before an important event the
next day). While some papers have utilized 6-month duration of the above
symptoms to define chronicity, there is evidence to suggest that as few as 30
days of symptoms are clinically important. Accordingly, for the purposes of
literature review, we have defined chronic insomnia as 30 days or more of the
symptoms described above.
The importance of sleep disruption often rests with its impact on the
individual’s daytime function. Guidelines incorporating impact on function
along with the above features in the definition of insomnia have recently been
published in an effort to standardize future insomnia research. However, the
impact of sleep disruption goes beyond the insomniac. When children and the
elderly (particularly nursing home residents) suffer from insomnia, parents and
caregivers also suffer. Employers of those with insomnia suffer when their work
performance is affected. Daytime drowsiness may make insomniacs dangerous as
Most cases of insomnia are comorbid with other conditions. Historically, this
has been termed “secondary insomnia.” However, the limited understanding of
mechanistic pathways in chronic insomnia precludes drawing firm conclusions
about the nature of these associations or the direction of causality.
Furthermore, there is concern that the term “secondary insomnia” may promote
undertreatment. Therefore, we propose that the term “comorbid insomnia” may be
more appropriate. Common comorbidities include psychiatric disorders,
particularly depression and substance use disorders; cardiopulmonary disorders;
and conditions associated with chronic somatic complaints (i.e.,
musculoskeletal syndromes such as rheumatoid arthritis or lower back pain) that
may disrupt sleep. Other associated sleep disorders can also contribute to
insomnia, particularly obstructive sleep apnea, restless legs syndrome, or
periodic limb movement disorder. “Primary insomnia” is the term used when no
co-existing disorder has been identified.
Diagnosis is based primarily on patient-derived and family or caregiver
complaints, as determined by the clinical interview. However, there has been
little research to show how accurately persons reporting sleep problems can
judge their own sleep latency or periods of wakefulness during the night.
Medical history and physical examination are useful in establishing the
presence of comorbid syndromes.
Other tools have been used as an aid to diagnosis, although many are limited in
their validation. Sleep diaries can help to document sleep/wake cycles. Various
questionnaires have been formulated, but there is a lack of standardization. An
actigraph, a wrist-worn device that measures movement to infer sleep and wake
cycles, is employed in the evaluation of circadian rhythm disorders, but its
use in insomnia has not been fully validated. Multichannel polysomnography,
either in-lab or at home, is the most sensitive tool to differentiate
wakefulness and sleep. However, polysomnography is expensive and because the
numerous monitoring electrodes can actually disrupt sleep, its use as a
diagnostic tool for insomnia should be limited to cases in which other sleep
disorders, such as sleep apnea, are suspected.
Classification and Etiology
Insomnia has been classified either based on its specific symptoms (i.e., sleep
onset or sleep maintenance) or the duration of the disorder. Etiology-based
classification schemes also have been advocated. Evidence supports both
psychological and physiological models in the etiology of insomnia.
Psychological models include the concepts of conditioning, hyperarousal, stress
response, predisposing personality traits, and attitudes and beliefs about
sleep. Physiological models have been explored in animals in an effort to
identify neural systems that regulate arousal and sleep. The precise
relationship between physical illness and changes in brain function that result
in insomnia remains uncertain.
2. What are the prevalence, natural history, incidence, and risk factors for
Although chronic insomnia is known to be common, studies of its prevalence have
yielded variable estimates (i.e., the proportion of persons who have the
disorder at a given point in time). Evidence from epidemiologic studies varies
depending on the definition of chronic insomnia and the diagnostic and
screening methods used. Population-based studies suggest that about 30 percent
of the general population complains of sleep disruption, while approximately 10
percent has associated symptoms of daytime functional impairment consistent
with the diagnosis of insomnia, though it is unclear what proportion of that 10
percent suffers from chronic insomnia. Not surprisingly, higher prevalence
rates are found in clinical practices, where about one-half of respondents
report symptoms of sleep disruption.
Few studies have described the course or duration of insomnia. Unpublished data
from a middle-aged population followed over 10 years describe a persistence of
symptoms. The limited prospective data on patients with sleep complaints of at
least a month’s duration showed that in the majority of insomniacs, symptoms
are of long duration. The paucity of literature describing the natural course
of insomnia underscores the need for large-scale longitudinal studies.
Very little is known about chronic insomnia’s incidence, which is the number of
new cases of the disorder arising in a specific time period, such as a year.
Because prevalence may be affected by events occurring after the insomnia is
under way, incident cases give the best information about the causes of
insomnia’s occurrence. Unfortunately, only a few studies have investigated the
incidence of chronic insomnia or the circumstances under which it first
appears. Increasing the number of studies of the incidence of chronic insomnia
is a clear research priority.
Research on the duration of chronic insomnia is also needed. The disorder can
last for relatively short periods of time in some patients and for decades in
others. Insomnia can also recur after a period of remission. When studies of
chronic insomnia incidence are conducted, the newly ascertained cases can be
followed longitudinally to describe the disorder’s natural history. In these
studies, it will be possible to investigate factors that are suspected of
affecting chronic insomnia’s duration, remissions, and relapses. It will be
particularly important to determine which therapies the treated patients
receive and their success in relieving symptoms or preventing relapses.
Several problems limit the ability to compare and integrate available
information from existing observational studies on correlates of insomnia: (1)
validated diagnostic instruments have not been applied in large,
population-based studies; (2) the many comorbid physical and psychiatric
conditions associated with a diagnosis of insomnia may be its cause, its
consequence, or share its risk factors. Because most studies have been
cross-sectional observations of affected persons rather than prospective
studies of persons beginning prior to the onset of insomnia, decisions cannot
be made as to which of its correlates are actually causal.
Many studies have found greater prevalence of insomnia among older people,
perhaps as a consequence of declining health and/or institutionalization.
Whether rates of insomnia increase with age in healthy older people remains
unclear. Most observational studies of insomnia have found greater prevalence
among women, especially in the postmenopausal years. Current evidence on
differences among racial or ethnic groups in prevalence of insomnia within the
United States is limited and inconclusive.
Several studies have found higher prevalence of insomnia in divorced, separated,
and widowed adults than in married adults. In some studies, lower education and
income have been associated with a higher prevalence of insomnia.
Several psychiatric and physical illnesses have strong relationships with
insomnia. Insomnia is a symptom of depression, so it is not surprising that a
diagnosis of depression is associated with insomnia. Other medical conditions,
including arthritis, heart failure, pulmonary and gastrointestinal disorders,
Parkinson’s disease, stroke, and incontinence, also affect sleep and increase
the prevalence of insomnia. The extent to which treatment for these conditions
ameliorates insomnia remains unclear.
Cigarette smoking, alcohol and coffee consumption, and consumption of certain
prescription drugs also affect sleep and are associated with increased
prevalence of insomnia. Although modification of these behaviors might be
expected to reduce the prevalence of insomnia, studies have yet to demonstrate
the effectiveness of these lifestyle changes as treatment for insomnia.
Validated instruments with known psychometric properties are needed, with
attention paid to ease of administration, cross-cultural applicability, and
comparability to objective measures of sleep performance, both overall and
within important subgroups. Attention is also needed concerning the reliable
measurement of the degree of sleep disturbance and the severity of symptoms of
Another hypothesis relates to the possible genetic etiology of insomnia. Work is
needed to quantify the importance of family history, along with a systematic
search for specific genes.
Correlates of insomnia should be explored for their relationships with the
development of subsequent insomnia. For example, studies are needed of the
impact on incidence of insomnia of divorce, separation and bereavement,
polypharmacy, and major chronic diseases.
Longitudinal observational studies are needed to identify factors affecting
incidence of and remission from insomnia. An efficient approach would be to add
validated questions on chronic insomnia to ongoing observational studies to
assess the many potential determinants of insomnia incidence, persistence, and
3. What are the consequences, morbidities, comorbidities, and public health
burden associated with chronic insomnia?
Consequences, Morbidities, and Comorbidities
Insomnia appears to be associated with high health care utilization. The direct
and indirect costs of chronic insomnia have been estimated at tens of billions
of dollars annually. However, these estimates depend on many assumptions. In
estimating the economic consequences of insomnia, it is difficult to separate
the effects of insomnia from the effects of comorbid conditions. For example, a
person with joint pain who has problems sleeping may seek health care for the
arthritis rather than for sleep problems, assuming that the pain accounts for
the sleep difficulty.
Only a few studies have examined the effects of insomnia on functioning in
everyday life. These studies suggest that insomnia reduces quality of life and
hinders social functioning. Two studies have identified a relationship between
chronic insomnia and work days missed. Other studies indicate that insomnia is
related to impaired work performance. There is at least some evidence of a
relationship between chronic insomnia and impaired memory and cognitive
Laboratory studies indicate that sleep loss results in impaired psychomotor and
cognitive functioning. There is evidence that chronic insomnia or the drugs
used to treat it contribute to the increased number of falls in older adults.
Insomnia usually appears in the presence of at least one other disorder.
Particularly common comorbidities are major depression, generalized anxiety,
substance abuse, attention deficit/hyperactivity in children, dementia, and a
variety of physical problems. The research diagnostic criteria for insomnia
recently developed by the American Academy of Sleep Medicine indeed share many
of the criteria of major depressive disorder. Studies to explain these overlaps
require determining how often insomnia precedes the disorders with which it is
associated and whether it continues to exist if the other disorders go into
Both insomnia and its treatment may adversely affect quality of life. Treatment
studies should include measures of undesirable side effects as well as the
reduction of symptoms of insomnia. Costs of illness and of treatment should be
assessed to allow for an analysis of the cost-effectiveness of treatments. The
U.S. Department of Health and Human Services has developed useful guidelines
for these assessments, and these should be consulted in the development of
evaluation protocols. In addition to measures of sleep symptoms, effects on
quality of life should also be measured.
Public Health Burden
The focus of public health is on populations rather than on individuals. The
public health consequences of insomnia are difficult to evaluate because the
literature is not well developed at this time. Sleep research has focused on
basic mechanisms and clinical studies. Relatively little attention has been
paid to the public health burden of insomnia. To better understand the public
health consequences of insomnia, several lines of research should be
The association of insomnia with premature death has not been studied.
Separating the effects of insomnia from the effects of its comorbidities will
be a methodological challenge. A start has been made by adding measures of
sleep to the National Health and Nutrition Examination Survey; such measures
should be added to other major epidemiological studies, including the
Behavioral Risk Factor Surveillance Survey.
The effect of insomnia on quality of life has been reported in few studies.
Secondary analysis of data from major population studies that include both
measures of sleep and measures of functioning and quality of life should be
supported. New studies are needed to determine whether insomnia causes
job-related disability. Furthermore, we need to support additional studies to
determine whether treatment for insomnia affects job performance and academic
The economic consequences of insomnia are not clearly understood. New studies
are needed to estimate the direct and indirect costs of chronic insomnia and
the potential societal benefits that might accrue from successful intervention
programs. Finally, insomnia has effects beyond individual patients. Families,
caregivers, and friends of the sufferers are also affected. More evidence is
needed to document these effects.
4. What treatments are used for the management of chronic insomnia, and what is
the evidence regarding their safety, efficacy, and effectiveness?
Epidemiological surveys have shown that the most common treatments used by
people with chronic insomnia are over-the-counter (OTC) antihistamines,
alcohol, and prescription medications. The major forms of psychological
treatments that have been systematically evaluated are the cognitive and
behavioral therapies. Alternative and complementary treatments include
melatonin and herbal remedies, such as valerian.
Assessment of the efficacy of treatments for chronic insomnia is complicated by
a number of factors. Studies said to have been carried out on subjects with
insomnia often lack consistency in the criteria used to diagnose chronic
insomnia, a history of the duration and severity of the insomnia, or agreement
on what effects of the treatment are to be evaluated. Further complicating the
ability to assess treatments for chronic insomnia is its overlap with many
medical and psychiatric conditions, most notably depression. Although there
have been RCTs for several treatments, there is inconsistency in applying
rigorous methodology to the assessment of a number of currently used
treatments. Additionally, most clinical trials are relatively short term. There
is a paucity of information about the long-term effects on sleep, daytime
functioning, and quality of life.
Behavioral and Cognitive Therapies
Behavioral and cognitive-behavioral therapies (CBTs) have demonstrated efficacy
in moderate to high-quality RCTs. Behavioral methods, which include relaxation
training, stimulus control, and sleep restriction, were developed and first
tested in the 1970s. More recently, cognitive therapy methods have been added
to behavioral methods. Cognitive therapy methods include cognitive
restructuring, in which anxiety-producing beliefs and erroneous beliefs about
sleep and sleep loss are specifically targeted. When these cognitive methods
have been added to the behavioral methods to compose a CBT package, it has been
found to be as effective as prescription medications are for short-term
treatment of chronic insomnia. Moreover, there are indications that the
beneficial effects of CBT, in contrast to those produced by medications, may
last well beyond the termination of active treatment. There is no evidence that
such treatment produces adverse effects, but thus far, there has been little,
if any, study of this possibility.
It is likely that most CBT is currently delivered by mental health practitioners
or physicians with formal sleep medicine training. However, CBT refers to a
number of varied nonpharmacologic treatments for insomnia, and a standardized
“best practice” model has yet to be formulated and validated. Thus, future
research should explore the optimum number and duration of sessions to yield
positive results, particularly as delivered in busy primary care practices
where the need and impact may be greatest.
Prescription medication therapy is intended to relieve symptoms of chronic
insomnia only while the medication is being taken. Given this expectation,
little or no research has been conducted on persistence or reappearance of
symptoms after prescription medication therapy is discontinued.
This section describes the use of two categories of medications, the
benzodiazepine receptor agonists that have been approved by the U.S. Food and
Drug Administration (FDA) for the treatment of insomnia and those that the FDA
has approved for the treatment of other disorders but which doctors often
prescribe to treat insomnia. The latter category is considered “off-label”
usage. There are currently eight medications approved by the FDA for treatment
of insomnia. Despite the fact that insomnia is often a chronic condition, only
one of these medications (eszopiclone) has been approved for use without a
specified time limit. The other medications have approved use limited to 35
days or less.
Benzodiazepine Receptor Agonists
Benzodiazepine receptor agonists fall into two broad groups of prescription
hypnotics: benzodiazepines (estazolam, flurazepam, quazepam, temazepam, and
triazolam) and the more recently introduced agents that act at benzodiazepine
receptors but have a nonbenzodiazepine structure (e.g., zaleplon, zolpidem, and
eszopiclone). Results from moderate to high-quality RCTs indicate that these
eight agents are effective in the short-term management of insomnia. With the
exception of eszopiclone, the benefits of these agents for long-term use have
not been studied using RCTs. A recent clinical trial of eszopiclone provided
evidence of sustained efficacy for 6 months in the treatment of subjects
meeting DSM-IV criteria for primary insomnia.
Adverse effects associated with these medications include residual daytime
sedation, cognitive impairment, motor incoordination, dependence, and rebound
insomnia. These problems appear to be worse in the elderly. The frequency and
severity of the adverse effects are much lower for the newer benzodiazepine
receptor agonists, most likely because these agents have shorter half-lives.
The available literature suggests that, in the short term, abuse of the
benzodiazepine receptor agonists is not a major problem, but problems
associated with their long-term use require further study in the general
population of insomniacs.
Prescription Drugs Used Without FDA Approval for Insomnia
Antidepressants. Over the past 20 years, there has been a significant change in
the use of prescription medications to treat chronic insomnia, with a decrease
in the use of benzodiazepine receptor agonists and a substantial increase in
the use of antidepressants. Based on recent surveys, the antidepressant
trazodone is now the most commonly prescribed medication for the treatment of
insomnia in the United States. In short-term use, trazodone is sedating and
improves several sleep parameters. These initial effects are known to last for
up to 2 weeks. Importantly, there are no studies of long-term use of trazodone
for treatment of chronic insomnia. Another antidepressant, doxepin, has been
found to have beneficial effects on sleep for up to 4 weeks for individuals
with insomnia. Data on other antidepressants (e.g., amitriptyline and
mirtazepine) in individuals with chronic insomnia are lacking. All
antidepressants have potentially significant adverse effects, raising concerns
about the risk–benefit ratio. There is a need to establish dose-response
relationships for all of these agents and communicate them to prescribers.
Other Prescription Medications. A number of other sedating medications have been
used in the treatment of insomnia. These include barbiturates (e.g.,
phenobarbital) and antipsychotics (e.g., quetiapine and olanzepine). Studies
demonstrating the usefulness of these medications for either short- or
long-term management of insomnia are lacking. Furthermore, all of these agents
have significant risks. Thus, their use in the treatment of chronic insomnia
cannot be recommended.
Nonprescription Medications (Over-the-Counter)
Antihistamines (H1 receptor antagonists such as diphenhydramine) are the most
commonly used OTC treatments for chronic insomnia, but there is no systematic
evidence for efficacy and there are significant concerns about risks of these
medications. Adverse effects include residual daytime sedation, diminished
cognitive function, and delirium, the latter being of particular concern in the
elderly. Other adverse effects include dry mouth, blurred vision, urinary
retention, constipation, and risk of increased intraocular pressure in
individuals with narrow angle glaucoma.
Many insomniacs take an alcoholic drink before bedtime in order to reduce sleep
latency. While alcohol does reduce sleep latency, drinking large amounts has
been shown to result in poorer quality of sleep and awakening during the night.
It is not known whether any impairment of sleep quality occurs when small
amounts are used at bedtime. The risk of excess alcohol consumption in persons
with alcohol problems makes this an inappropriate treatment for them.
Melatonin is a natural hormone produced by the pineal gland that plays a role in
the control of circadian rhythms. Because melatonin is not regulated by the
FDA, preparations containing it vary in strength, making comparisons across
studies difficult. Although melatonin appears to be effective for the treatment
of circadian rhythm disorders (e.g., jet-lag), little evidence exists for
efficacy in the treatment of insomnia or its appropriate dosage. In short-term
use, melatonin is thought to be safe, but there is no information about the
safety of long-term use.
Valerian is derived from the root of the plant species valeriana and is thought
to promote sleep. Limited evidence shows no benefit compared with placebo. The
FDA does not regulate valerian, and thus different preparations vary in
valerian content. Safety data are minimal, but there have been case reports of
hepatotoxicity in persons taking herbal products containing valerian. Other
herbal remedies have also been promoted, but efficacy evidence is lacking.
L-tryptophan is an endogenous amino acid that has been used as a hypnotic.
Systematic evidence supporting its use in the treatment of insomnia is
extremely limited and based on studies with small numbers of subjects. Concerns
are also raised about its possible toxic effects, particularly when used in
combination with certain psychiatric medications.
There are a number of alternative activities, including tai chi, yoga,
acupuncture, and light therapy, that may be useful in the treatment of
insomnia. These treatments have not been adequately evaluated at this time.
CBT and benzodiazepine receptor agonists have demonstrated efficacy in the acute
management of chronic insomnia. However, full evaluation of the effectiveness
of these therapies for chronic insomnia will require trials of longer duration
that measure health outcomes—including the ability of treatments to ameliorate
the daytime impairment related to sleep difficulty—and also integrate the risks
and benefits of treatment.
Other therapies have also demonstrated some promise. However, little is known
about the comparative benefits of these treatments, their generalizability, and
their effects on understudied features of chronic insomnia.
In order to address this lack of knowledge, RCTs will be required that:
Are large-scale and multisite.
Compare at least two effective or promising treatments so that the comparative
benefits of effective treatments can be evaluated. This should include
comparisons among pharmacological agents, CBT, and combined treatment.
Evaluate the positive and adverse effects of treatments over longer timeframes,
including the period after discontinuation of treatment.
Incorporate objective and subjective measures of daytime function and quality
of life in addition to the traditional parameters of sleep, such as sleep onset
latency and total sleep time.
Systematically evaluate a variety of commonly used OTC and alternative remedies
for insomnia that have not been formally evaluated.
Measure the costs and cost-effectiveness of treatments.
The pharmaceutical industry is called upon to support comparisons of its
medications not only with placebo but also with other effective treatments,
Studies should be directed to important population subgroups, including
children, nursing home residents, postmenopausal women, those with primary
chronic insomnia, and those with insomnia comorbid with other conditions.
To overcome reporting bias in clinical trials, in which positive results are
published while negative results are not, the development of a central registry
for all insomnia trials is recommended. This registry would allow a
systematic synthesis of the available clinical trial data.
As data from RCTs showing efficacy become available, it will be critical to
evaluate effectiveness in broader clinical populations in community settings.
RCT study subjects for whom the tested substance appeared to be effective need
to be followed over time, with random assignment to varying times at which the
drug will be discontinued. These studies will give evidence for the appearance
of side effects with long-term use, for the development of tolerance to the
drug in time, and for any lasting beneficial effects after discontinuation of
Repeated surveys of physician prescribing behavior and decision making are
recommended to permit an understanding of how their treatment behavior changes
as new data on efficacy of insomnia treatments become available. Such studies
will show whether substantial re-education programs for physicians should be
5. What are important future directions for insomnia-related research?
Validated instruments are needed to assess chronic insomnia, with attention paid
to the ease of administration and cross-cultural applicability. A greater range
of outcome measures related to chronic insomnia and its consequences is also
needed. Measures of sleep should be added to longitudinal epidemiologic studies
that are collecting data on a broad range of items that could turn out to be
risk factors for insomnia.
Studies are needed of the possible genetic etiology of chronic insomnia. The
neural mechanisms underlying chronic insomnia are poorly understood. Studies
aiming to identify neural mechanisms should use animal models and in vivo
neural imaging approaches in people with insomnia and in individuals with
normal sleep. Work is needed to quantify the importance of family history,
along with a systematic search for specific genes.
Longitudinal observational studies are needed to identify factors affecting
incidence of, natural history of, and remission from chronic insomnia. An
efficient approach would be to add questions about chronic insomnia to ongoing
observational studies that assess the many potential determinants of insomnia
incidence, persistence, and remission.
The effects of insomnia on quality of life have been reported in few studies.
Analyses of data from major population studies that include measures of sleep,
measures of functioning, and quality of life should be supported. Studies are
needed to determine whether insomnia causes job-related disability and whether
treatment for insomnia enhances job performance and academic performance.
Studies are needed to estimate the direct and indirect societal costs of
insomnia and the potential societal benefits that might accrue from successful
intervention programs. Moreover, because chronic insomnia has effects that go
beyond individual patients, more research is needed to quantify effects on
families, friends, and caregivers of insomniacs.
CBT and benzodiazepine receptor agonists have been shown to be beneficial in the
acute management of chronic insomnia. Other therapies have also demonstrated
some promise. However, little is known about the comparative benefits of these
treatments, their combination, and their effects on understudied features of
chronic insomnia. To address this lack of knowledge, RCTs will be required that
are large scale and multisite and compare at least two effective or promising
treatments. This should include comparisons between pharmacological agents as
well as between those agents and CBT. The pharmaceutical industry is called
upon to compare its medications not only with placebo but also with other
effective treatments, including CBT. Trials should include measures of cost and
To overcome potential problems with reporting bias in clinical trials, the
development of a central registry for all clinical trials is recommended. This
registry would allow a systematic synthesis of the available clinical trial
As comparative efficacy data become available, it will be critical to conduct
effectiveness studies to determine generalizability to broader clinical
populations in community settings.
Studies should be directed to important population subgroups, including
children, nursing home residents, postmenopausal women, those with primary
chronic insomnia, and those with insomnia comorbid with other conditions.
Chronic insomnia is a major public health problem affecting millions of
individuals, along with their families and communities. Little is known about
the mechanisms, causes, clinical course, comorbidities, and consequences of
chronic insomnia. Evidence supports the efficacy of cognitive-behavioral
therapy and benzodiazepine receptor agonists in the treatment of this disorder,
at least in the short term. Very little evidence supports the efficacy of other
treatments, despite their widespread use. Moreover, even for those treatments
that have been systematically evaluated, the panel is concerned about the
mismatch between the potential lifelong nature of this illness and the longest
clinical trials, which have lasted 1 year or less. A substantial public and
private research effort is warranted, including developing research tools and
conducting longitudinal studies of randomized clinical trials. Finally, there
is a major need for educational programs directed at physicians, health care
providers, and the public.