Background Although insomnia is a prevalent complaint with significant morbidity, it often remains unrecognized and untreated. Brief and valid instruments are needed both for screening and outcome assessment. This study examined psychometric indices of the Insomnia Severity Index (ISI) to detect cases of insomnia in a population-based sample and to evaluate treatment response in a clinical sample. Methods Participants were 959 individuals selected from the community for an epidemiological study of insomnia (Community sample) and 183 individuals evaluated for insomnia treatment and 62 controls without insomnia (Clinical sample). They completed the ISI and several measures of sleep quality, fatigue, psychological symptoms, and quality of life; those in the Clinical sample also completed sleep diaries, polysomnography, and interviews to validate their insomnia/good sleep status and assess treatment response. In addition to standard psychometric indices of reliability and validity, item response theory analyses were computed to examine ISI item response patterns. Receiver operating curves were used to derive optimal cutoff scores for case identification and to quantify the minimally important changes in relation to global improvement ratings obtained by an independent assessor. Results ISI internal consistency was excellent for both samples (Cronbach α of 0.90 and 0.91). Item response analyses revealed adequate discriminatory capacity for 5 of the 7 items. Convergent validity was supported by significant correlations between total ISI score and measures of fatigue, quality of life, anxiety, and depression. A cutoff score of 10 was optimal (86.1% sensitivity and 87.7% specificity) for detecting insomnia cases in the community sample. In the clinical sample, a change score of -8.4 points (95% CI: -7.1, -9.4) was associated with moderate improvement as rated by an independent assessor after treatment. Conclusion These findings provide further evidence that the ISI is a reliable and valid instrument to detect cases of insomnia in the population and is sensitive to treatment response in clinical patients.

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The Insomnia Severity Index: psychometric indicators to detect insomnia cases and evaluate treatment response.

Insomnia is the most prevalent sleep disorder in the general population, and is commonly encountered in medical practices. Insomnia is defined as the subjective perception of difficulty with sleep initiation, duration, consolidation, or quality that occurs despite adequate opportunity for sleep, and that results in some form of daytime impairment.1 Insomnia may present with a variety of specific complaints and etiologies, making the evaluation and management of chronic insomnia demanding on a clinician's time. The purpose of this clinical guideline is to provide clinicians with a practical framework for the assessment and disease management of chronic adult insomnia, using existing evidence-based insomnia practice parameters where available, and consensus-based recommendations to bridge areas where such parameters do not exist. Unless otherwise stated, "insomnia" refers to chronic insomnia, which is present for at least a month, as opposed to acute or transient insomnia, which may last days to weeks.

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Clinical Guideline for the Evaluation and Management of Chronic Insomnia in Adults

https://tud.qucosa.de/api/qucosa%3A26871/attachment/ATT-0/

Cost of disorders of the brain in Europe 2010

Study objectives: To present an expert consensus, standardized, patient-informed sleep diary. 

Methods and results: Sleep diaries from the original expert panel of 25 attendees of the Pittsburgh Assessment Conference(1) were collected and reviewed. A smaller subset of experts formed a committee and reviewed the compiled diaries. Items deemed essential were included in a Core sleep diary, and those deemed optional were retained for an expanded diary. Secondly, optional items would be available in other versions. A draft of the Core and optional versions along with a feedback questionnaire were sent to members of the Pittsburgh Assessment Conference. The feedback from the group was integrated and the diary drafts were subjected to 6 focus groups composed of good sleepers, people with insomnia, and people with sleep apnea. The data were summarized into themes and changes to the drafts were made in response to the focus groups. The resultant draft was evaluated by another focus group and subjected to lexile analyses. The lexile analyses suggested that the Core diary instructions are at a sixth-grade reading level and the Core diary was written at a third-grade reading level. 

Conclusions: The Consensus Sleep Diary was the result of collaborations with insomnia experts and potential users. The adoption of a standard sleep diary for insomnia will facilitate comparisons across studies and advance the field. The proposed diary is intended as a living document which still needs to be tested, refined, and validated.

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The Consensus Sleep Diary: Standardizing Prospective Sleep Self-Monitoring

The hyperarousal model of insomnia: A review of the concept and its evidence

Epidemiology of insomnia: prevalence, self-help treatments, consultations, and determinants of help-seeking behaviors.

INSOMNIA IS A PREVALENT PUBLIC HEALTH PROBLEM, WITH BETWEEN 6% AND 10% OF THE POPULATION MEETING DIAGNOSTIC CRITERIA FOR INSOMNIA syndrome1–3 and about a third of the population experiencing insomnia symptoms at any given moment.2 Despite its high prevalence, there is little information on the economic burden of insomnia. Information on the costs of illnesses, an indicator of their burden to society, is increasingly driving policy decisions about the funding and development of health care and research programs and priorities. Insurance companies are also concerned with the costs of illnesses and the impact that interventions may have in reducing symptoms and health care system utilization.

Economic evaluations of the cost of illnesses or the cost effectiveness of treatments consider 2 broad categories of costs. These include direct costs associated with the consumption of resources (e.g., consultations, products, and testing), and indirect costs associated with the loss of resources (e.g., absenteeism, reduced productivity).4 While studies show a relationship between insomnia severity and the use of health-care service and product utilization,5–9 quantification of the associated costs is scarce. Similarly, some studies have reported a relationship between insomnia, increased absenteeism, and decreased productivity,10–13 yet the economic burden of this has been less frequently measured.

The National Commission on Sleep Disorders Research estimated the direct costs of insomnia in the United States at $13.9 billion for the year 1995,14 whereas Leger et al.15 estimated the total cost of insomnia in France at about 10 million francs (or $2 billion US). The indirect costs associated with insomnia have received less attention in the literature, primarily because these costs are more difficult to estimate and quantify, there is no single database from which to draw, and measurement of these variables is more subject to interpretation and memory bias. Stoller16 attempted to quantify work-related deficits by combining data obtained in a study of workplace performance in Navy servicemen17 with her own insomnia prevalence estimate of 33% and a performance decrement estimate of 4%. The monetary value of absenteeism and lost productivity was estimated at $41.1 billion annually (1995 US$). A per person estimate was attempted by Chilcott and Shapiro,5 who suggest a decrease in work productivity due to insomnia of 10%. This amounts to $3,000 per insomnia sufferer per year. Stoller16 also looked at a number of other indirect costs, including insomnia-related accidents, alcoholism, and depression, estimating their costs at between $77.05 and $92.13 billion. Although these estimates have been criticized because they are based on liberal prevalence rates and relied on some questionable assumptions,9 they are still frequently used to describe the indirect economic consequences of insomnia.

A French study18 concluded that insomnia is associated with increased absenteeism and reduced productivity, with associated costs about twice as high for insomnia patients as for good sleepers. The methods of costing did not allow, however, for an analysis of the proportional contribution of insomnia. There was also a methodological problem associated with double-counting costs that may have inflated cost estimates. Using existing data banks, Hillman et al.19 estimated the financial costs of all sleep disorders combined (e.g., insomnia, sleep apnea, periodic limb movements) for Australia at about $1,524 million, or 0.8% of the Australian gross domestic product. While an innovative approach was used to estimate fractions of other health impacts attributable to sleep disorders, this study did not permit the identification of costs associated with individual sleep disorders.

A recent study by Ozminkowski et al.20 used medical claims data for health-care services, and absenteeism and short-term disability records to assess costs of insomnia occurring in adults in the US. After matching adult (aged 18–64) subsamples on variables determined by propensity score analysis, indirect costs combined were $1,253 higher in individuals with insomnia as compared to those without insomnia. The matching procedure and use of objective data lend strength to this study. However, costs related to reduced productivity, transportation, use of alcohol, and use of over-the-counter products were excluded from the analysis, suggesting that the results may underestimate the real cost of insomnia.

Despite recent progress in documenting the economic burden of insomnia, some methodological weaknesses limit the current state of knowledge on this topic. The use of large administrative databases precludes analysis of potential confounding variables such as the reasons for consultations, use of OTC products, actual consumption of prescribed medications and, for some medications, the target ailment for which it was prescribed. When workplace records are used to obtain absenteeism data, reasons for absences are rarely provided and productivity data are not available. Similarly, the use of official accident records precludes identification of the contributing role of insomnia to these events. Studies typically use 2 groups—individuals with and without insomnia; the inclusion of an intermediate category would allow analysis of a linear relationship between costs and insomnia severity.

The purpose of this study was to estimate, from the societal perspective, direct and indirect costs of insomnia. Costs were compared across three groups of participants classified as being good sleepers, having insomnia symptoms or having insomnia syndrome. The proportional contribution of insomnia to overall consultation costs and three indirect dependent cost variables, absenteeism, productivity and accidents, was also calculated.

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The Economic Burden of Insomnia: Direct and Indirect Costs for Individuals with Insomnia Syndrome, Insomnia Symptoms, and Good Sleepers

Background Despite its high prevalence, little information is available about the natural history of insomnia. The extent to which episodes of insomnia will persist or remit over time is difficult to predict. We examined the natural history of insomnia and describe the most common trajectories over 3 years. Methods Three hundred eighty-eight adults (mean [SD] age, 44.8 [13.9] years; 61% women) were selected from a larger population-based sample on the basis of the presence of insomnia at baseline. They completed standardized sleep/insomnia questionnaires at 3 annual follow-up assessments. For each follow-up assessment, participants were classified into 1 of 3 groups (individuals with an insomnia syndrome, individuals with insomnia symptoms, and individuals with good sleep) on the basis of algorithms using standard diagnostic criteria for insomnia. Rates of persistent insomnia, remission, and relapse were computed for each group. Results Of the study sample, 74% reported insomnia for at least 1 year (2 consecutive assessments) and 46% reported insomnia persisting over the entire 3-year study. The course of insomnia was more likely to be persistent in those with more severe insomnia at baseline (ie, insomnia syndrome) and in women and older adults. Remission rate was 54%; however, 27% of those with remission of insomnia eventually experienced relapse. Individuals with subsyndromal insomnia at baseline were 3 times more likely to remit than worsen to syndrome status, although persistence was the most frequent course in that group as well. Conclusion These findings indicate that insomnia is often a persistent condition, in particular when it reaches the diagnostic threshold for an insomnia disorder.

/pdf/the-natural-history-of-insomnia-a-population-based-3-year-2fl8n3y4je.pdf

The Natural History of Insomnia : A Population-Based 3-Year Longitudinal Study

INSOMNIA IS AMONG THE MOST PREVALENT HEALTH COMPLAINTS. APPROXIMATELY 9% OF THE GENERAL POPULATION REGULARLY SUFFER FROM INSOMNIA, and about 30% do so occasionally.1–3 Incidence rates reported in longitudinal studies vary extensively (from 3% to 20%), depending on the population studied, the time interval (e.g., 1 year versus 10 years), and the definition of insomnia used (i.e., insomnia syndrome versus symptoms). For instance, it is estimated that over a period of one year, approximately 6% of the general population develop an insomnia syndrome,4 and approximately 20% develop insomnia symptoms, with the latter figures being based on samples of older adults5 and individuals with chronic health problems.6 Furthermore, new onset of insomnia is generally more frequent among women and individuals with medical conditions, psychiatric disorders, and a perceived stressful life.4,7–9

Based on a tripartite conceptual framework widely used to explain the development of insomnia,10–12 3 types of factors are involved at different times during the course of insomnia. First, everyone is, to some degree, predisposed to develop insomnia. Second, a precipitating event is usually associated with the onset of insomnia. Third, insomnia is perpetuated over time by psychological and behavioral factors, even after precipitating factors have been controlled or eliminated. The most commonly hypothesized predisposing factors include demographic factors (e.g., aging, female gender, living alone),1,3,13 familial/hereditary conditions (a personal or family history of insomnia),14–16 psychological factors (e.g., anxiety, depression, personality traits),4,17–19 and physiological and lifestyle factors (e.g., arousability and smoking).20,21 Precipitating factors include stressful life events (e.g., divorce),9,22 as well as psychological and health-related factors (e.g., pain, mental health problems).10,23 Finally, maintaining factors include maladaptive sleep habits (e.g., excessive amounts of time spent in bed, napping, chronic medication use) and dysfunctional cognitions about sleep loss and its impact on life (e.g., worry over sleep loss).10

Most studies investigating insomnia risk factors have been either retrospective or cross-sectional, precluding unequivocal inference about the relationship between these factors and the development of insomnia. The extent to which depression and anxiety trigger insomnia or represent consequences of insomnia remains ambiguous. The few longitudinal studies of insomnia have provided informative data about incidence and risk factors, although most of those studies have focused predominantly on selected samples such as young adults,7,28 elderly adults,8,24,25 or patients attending medical practices.6,26,27 Only one longitudinal study evaluating the relation between sleep problem symptoms (i.e., insomnia and hypersomnia) and psychiatric disorders sampled the population at large.4

Few studies have used standard diagnostic criteria to define insomnia. Moreover, previous studies have used various time frames and most have not adequately operationalized their measure of incidence. For instance, most studies have not differentiated between incident cases of first episode of insomnia (no prior history of insomnia) and cases of recurrence (with past history of insomnia). Furthermore, the majority of studies included only individuals experiencing insomnia at the time of the second assessment in their incidence estimates5,6,8,29 rather than all cases emerging during the interval between baseline and follow-up assessment.7 Since insomnia may prove transient or episodic, incidence rates may have been underestimated in previous studies. The National Institutes of Health30 called for additional longitudinal studies using well-operationalized and stringent diagnostic criteria to estimate insomnia incidence and identify risk factors within the general population.

The objectives of this study were to estimate the incidence of insomnia symptoms and syndrome and to identify associated risk factors in a cohort of good sleepers sampled from the general population and followed over a one-year period.

/pdf/incidence-and-risk-factors-of-insomnia-in-a-population-based-nlodrd0i9g.pdf

Incidence and risk factors of insomnia in a population-based sample.

https://corpus.ulaval.ca/jspui/bitstream/20.500.11794/32803/1/Art_2009_Sleep%20Med%20%28Daley%20et%20al%29.pdf

Mélanie LeBlanc

Papers

Epidemiology of insomnia: prevalence, self-help treatments, consultations, and determinants of help-seeking behaviors.

The Economic Burden of Insomnia: Direct and Indirect Costs for Individuals with Insomnia Syndrome, Insomnia Symptoms, and Good Sleepers

The Natural History of Insomnia : A Population-Based 3-Year Longitudinal Study

Incidence and risk factors of insomnia in a population-based sample.

Insomnia and its relationship to health-care utilization, work absenteeism, productivity and accidents.