Subtyping DSM-III-R primary insomnia: a literature review by the DSM-IV Work Group on Sleep Disorders

Insomnia nosology: a systematic review and critical appraisal of historical diagnostic categories and current phenotypes

Insomnia nosology has significantly evolved since the Diagnostic and Statistical Manual (DSM)-III-R first distinguished between 'primary' and 'secondary' insomnia. Prior International Classification of Sleep Disorders (ICSD) nosology 'split' diagnostic phenotypes to address insomnia's heterogeneity and the DSM nosology 'lumped' them into primary insomnia, while both systems assumed causality for insomnia secondary to health conditions. In this systematic review, we discuss the historical phenotypes in prior insomnia nosology, present findings for currently proposed insomnia phenotypes based on more robust approaches, and critically appraise the most relevant ones. Electronic databases PsychINFO, PubMED, Web of Science, and references of eligible articles, were accessed to find diagnostic manuals, literature on insomnia phenotypes, including systematic reviews or meta-analysis, and assessments of the reliability or validity of insomnia diagnoses, identifying 184 articles. The data show that previous insomnia diagnoses lacked reliability and validity, leading current DSM-5-TR and ICSD-3 nosology to 'lump' phenotypes into a single diagnosis comorbid with health conditions. However, at least two new, robust insomnia phenotyping approaches were identified. One approach is multidimensional-multimethod and provides evidence for self-reported insomnia with objective short versus normal sleep duration linked to clinically relevant outcomes, while the other is multidimensional and provides evidence for two to five clusters (phenotypes) based on self-reported trait, state, and/or life-history data. Some approaches still need replication to better support whether their findings identify true phenotypes or simply different patterns of symptomatology. Regardless, these phenotyping efforts aim at improving insomnia nosology both as a classification system and as a mechanism to guide treatment.

Insomnia, Medicalization, and Expert Knowledge

Historians have clearly articulated the ways in which sleeplessness has long been part of the human condition. As an object of medical expertise and public health intervention, however, insomnia is a much more recent invention, having gained its status as a pathology during the 1870s. But while insomnia has attracted considerable and concerted attention from public health authorities allied with sleep medicine specialists, this phenomenon is not well explained by classical medicalization theory, in part because it is the sleepless sufferers, not the medical experts, who typically have the authority to diagnose insomnia. The dynamics of insomnia's history are better described as those of a boundary object, around which concepts and practices of biomedicine and psychology coalesce to frame contemporary notions of self-medicalization and self-experiment.

The top 100 most cited papers in insomnia: A bibliometric analysis

OBJECTIVE

The number of citations to a paper represents the weight of that work in a particular area of interest. Several highly cited papers are listed in the bibliometric analysis. This study aimed to identify and analyze the 100 most cited papers in insomnia research that might appeal to researchers and clinicians.

METHODS

We reviewed the Web of Science (WOS) Core Collection database to identify articles from 1985 to 24 March 2022. The R bibliometric package was used to further analyze citation counts, authors, year of publication, source journal, geographical origin, subject, article type, and level of evidence. Word co-occurrence in 100 articles was visualized using VOS viewer software.

RESULTS

A total of 44,654 manuscripts were searched on the Web of Science. Between 2001 and 2021, the top 100 influential manuscripts were published, with a total citation frequency of 38,463. The top countries and institutions contributing to the field were the U.S. and Duke University. Morin C.M. was the most productive author, ranking first in citations. Sleep had the highest number of manuscripts published in the top 100 (n = 31), followed by Sleep Medicine Reviews (n = 9). The most cited manuscript (Bastien et al., Sleep Medicine, 2001; 3,384 citations) reported clinical validation of the Insomnia Severity Index (ISI) as a brief screening indicator for insomnia and as an outcome indicator for treatment studies. Co-occurrence analyses suggest that psychiatric disorders combined with insomnia and cognitive behavioral therapy remain future research trends.

CONCLUSION

This study provides a detailed list of the most cited articles on insomnia. The analysis provides researchers and clinicians with a detailed overview of the most cited papers on insomnia over the past two decades. Notably, COVID-19, anxiety, depression, CBT, and sleep microstructure are potential areas of focus for future research.

Insomnia Disorders: Nosology and Classification Past, Present, and Future

Insomnia is the most common sleep disorder in the adult population. However, the definition of insomnia disorder has varied across major classification systems and changed over time. In the present study, the investigators traced the evolution of insomnia disorder across classification systems, contemplated the empirical basis for its current definitions, and surveyed ongoing research efforts that may clarify insomnia nosology in the future. Three major classification systems for insomnia are the International Classification of Sleep Disorders, the International Classification of Diseases, and DSM. Despite their divergent origins, these classification systems have converged to nearly identical contemporary insomnia definitions. Over time, the emphasis in classification approaches has shifted from symptomatology to etiology to treatment implications. Additionally, the historical multitude of insomnia subtypes has gradually consolidated into a few core diagnoses, reflecting inadequate evidence with which to support subtyping. Current insomnia definitions include frequency and duration criteria to operationalize these diagnoses, while the diagnostic criterion of nonrestorative sleep has been eliminated (with some controversy). In ongoing research efforts, the quest for insomnia biomarkers has not thus far yielded clinically deployable breakthroughs. Data-driven insomnia subtyping suggests a promising new approach in deriving empirically based subtypes; conversely, the transdiagnostic perspective proposes the elimination of categorical distinctions in favor of finding common processes underlying all psychiatric disorders. The continual evolution of insomnia nosology highlights that much remains to be learned about these conditions; all current diagnostic classification systems are best regarded as "works in progress." Nevertheless, refinement and convergence of classification approaches is essential to standardizing insomnia research, diagnosis, and treatment.

Objective sleep disturbance is associated with poor response to cognitive and behavioral treatments for insomnia in postmenopausal women

STUDY OBJECTIVES

To determine whether insomnia patients with objective sleep disturbance are less responsive to cognitive and behavioral treatments than those without objective sleep disturbance, characterize effects of insomnia therapy on objective sleep, and determine whether reductions in nocturnal cognitive arousal correspond to changes in objective sleep.

METHODS

Secondary analysis of a single-site, randomized controlled trial. 113 postmenopausal women (56.40 ± 5.34 years) with menopause-related insomnia disorder were randomized to three treatment conditions: cognitive-behavioral therapy for insomnia (CBTI), sleep restriction therapy (SRT), or sleep education control. Primary outcomes were the Insomnia Severity Index (ISI) and polysomnography (PSG) sleep parameters and were collected at pretreatment, posttreatment, and six-month follow-up.

RESULTS

Patients with lower pretreatment PSG sleep efficiency had lower rates of insomnia remission after active treatment relative to those with higher sleep efficiency (37.8% vs 61.8%). Neither CBTI and SRT produced clinically meaningful effects on PSG sleep. Exploratory analyses revealed that reductions in nocturnal cognitive arousal were associated with decreases in PSG sleep latency, but not wake after sleep onset.

CONCLUSIONS

Our findings support an emerging literature suggesting that insomnia patients with objective sleep disturbance may have blunted response to insomnia therapy. Research is needed to enhance treatments to better improve insomnia in patients with objective sleep disturbance. A lack of observed CBTI and SRT effects on PSG sleep suggests that these therapies may be presently ill-designed to improve objective sleep. Nocturnal cognitive arousal may represent an entry point to improve objective sleep latency in insomnia. NAME: Behavioral Treatment of Menopausal Insomnia: Sleep and Daytime Outcomes. URL: clinicaltrials.gov. Registration: NCT01933295.

Temperament and character in primary insomnia

Recent studies by Cloninger suggest that the temperament dimension of harm avoidance might be related to serotonergic activity. Since serotonergic mechanisms equally play a major role in sleep regulation, we decided to use Cloninger’s psychobiological model of temperament and character to assess whether there is a link between psychophysiologic insomnia and specific personality traits. Chronic insomnia is a common complaint in modern society, and it is still controversial whether insomniacs share specific personality traits. Thirty-two chronic insomniacs (<50 years) were studied. They underwent polysomnography for two consecutive nights and filled out the 226-item self-questionnaire of Temperament and Character Inventory as well as the Hospital Anxiety and Depression scale. (1) Harm avoidance for all subscores was significantly higher in insomniac patients when compared with controls; (2) self-directedness scores were lower in insomniacs; (3) sleep latency was positively correlated to harm avoidance; (4) HA1 (anticipatory worry) was negatively correlated to REM latency. Temperament and Character Inventory is a useful tool in the investigation of chronic insomnia. Serotonergic mechanisms might explain the high incidence of harm avoidance as personality trait in psychophysiologic insomniac patients. Further studies are needed to see whether harm avoidance could be a psychological vulnerability marker for primary insomnia and be used as predictor of SSRI treatment responders.

Therapeutic efficacy of zolpidem combined with cognitive-behavioral therapy on primary insomnia

BACKGROUND

In this study, we intend to assess the efficacy of zolpidem combined with cognitive-behavioral therapy (CBT) for patients with primary insomnia (PI).

METHODS

A predefined search strategy will be used to search for associated literature from inception to the July 1, 2019: PubMed, EMBASE, Cochrane Library, Scopus, Web of Science, Google Scholar, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure with no language limitation. In addition, we will also retrieve reference lists of included studies and relevant reviews, as well as the conference proceedings. All randomized controlled trials related to the zolpidem and CBT for PI will be included. Two authors will perform study selection, data collection, and study quality, respectively. We will also apply RevMan 5.3 software for statistical analysis.

RESULTS

This study will provide a comprehensive overview of the available evidence of the benefits and safety of zolpidem and CBT for PI. Primary outcomes are sleep quality and severity of sleep disorders. Secondary outcomes consist of sleep-onset latency, total sleep duration, sleep efficiency, and frequency and adverse events.

CONCLUSION

The results of this study will inform clinical and policy decisions regarding the benefits and harm of zolpidem and CBT for patients with PI.

PROSPERO REGISTRATION NUMBER

PROSPERO CRD42019142796.

All-night functional magnetic resonance imaging sleep studies

BACKGROUND

Previous functional magnetic resonance imaging (fMRI) sleep studies have been hampered by the difficulty of obtaining extended amounts of sleep in the sleep-adverse environment of the scanner and often have resorted to manipulations such as sleep depriving subjects before scanning. These manipulations limit the generalizability of the results.

NEW METHOD

The current study is a methodological validation of procedures aimed at obtaining all-night fMRI data in sleeping subjects with minimal exposure to experimentally induced sleep deprivation. Specifically, subjects slept in the scanner on two consecutive nights, allowing the first night to serve as an adaptation night.

RESULTS/COMPARISON WITH EXISTING METHOD(S)

Sleep scoring results from simultaneously acquired electroencephalography data on Night 2 indicate that subjects (n = 12) reached the full spectrum of sleep stages including slow-wave (M = 52.1 min, SD = 26.5 min) and rapid eye movement (REM, M = 45.2 min, SD = 27.9 min) sleep and exhibited a mean of 2.1 (SD = 1.1) nonREM-REM sleep cycles.

CONCLUSIONS

It was found that by diligently applying fundamental principles and methodologies of sleep and neuroimaging science, performing all-night fMRI sleep studies is feasible. However, because the two nights of the study were performed consecutively, some sleep deprivation from Night 1 as a cause of the Night 2 results is likely, so consideration should be given to replicating the current study with a washout period. It is envisioned that other laboratories can adopt the core features of this protocol to obtain similar results.

Exploring the impact of experimental sleep restriction and sleep deprivation on subjectively perceived sleep parameters

We aimed to investigate the effect of increased sleep pressure and shortened sleep duration on subjective sleep perception in relation to electroencephalographic sleep measures. We analyzed the data from a study in which 14 healthy male volunteers had completed a baseline assessment with 8 hr time in bed, a sleep deprivation (40 hr of wakefulness) and a sleep restriction protocol with 5 hr time in bed during 7 nights. In this work, we assessed perception index, derived through dividing the subjectively perceived total sleep time, wake after sleep onset and sleep latency duration by the objectively measured one at each condition. We found that total sleep time was subjectively underestimated at baseline and shifted towards overestimation during sleep restriction and after deprivation. This change in accuracy of subjective estimates was not associated with any changes in sleep architecture or sleep depth. Wake after sleep onset was significantly underestimated only during sleep restriction. Sleep latency was always overestimated subjectively without any significant change in this misperception across conditions. When comparing accuracy of subjective and actimetry estimates, subjective estimates regarding total sleep time and wake after sleep onset deviated less from electroencephalography derived measures during sleep restriction and after deprivation. We conclude that self-assessments and actimetry data of patients with chronic sleep restriction should be interpreted cautiously. The subjectively decreased perception of wake after sleep onset could lead to overestimated sleep efficiency in such individuals, whereas the underestimation of sleep time and overestimation of wake after sleep onset by actimetry could lead to further underestimated sleep duration.

Experience of sleep disruption in primary Sjögren's syndrome: A focus group study

INTRODUCTION

Primary Sjögren's syndrome is the third most common systemic autoimmune rheumatic disease, following rheumatoid arthritis and systemic lupus erythematosus, and results in dryness, fatigue, discomfort and sleep disturbances. Sleep is relatively unexplored in primary Sjögren's syndrome. We investigated the experiences of sleep disturbances from the viewpoint of primary Sjögren's syndrome patients and their partners and explored the acceptability of cognitive behavioural therapy for insomnia.

METHOD

We used focus groups to collect qualitative data from 10 patients with primary Sjögren's syndrome and three partners of patients. The data were recorded, transcribed verbatim and analysed using thematic analysis.

RESULTS

Five themes emerged from the data: (a) Experience of sleep disturbances; (b) variation and inconsistency in sleep disturbances; (c) the domino effect of primary Sjögren's syndrome symptoms; (d) strategies to manage sleep; (e) acceptability of evidence-based techniques. Sleep disturbances were problematic for all patients, but specific disturbances varied between participants. These included prolonged sleep onset time and frequent night awakenings and were aggravated by pain and discomfort. Patients deployed a range of strategies to try and self-manage. Cognitive behavioural therapy for insomnia was seen as an acceptable intervention, as long as a rationale for its use is given and it is tailored for primary Sjögren's syndrome.

CONCLUSION

Primary Sjögren's syndrome patients described a range of sleep disturbances. Applying tailored, evidence-based sleep therapy interventions may improve sleep, severity of other primary Sjögren's syndrome symptoms and functional ability.

Paradoxical insomnia and subjective-objective sleep discrepancy: A review

Paradoxical insomnia is characterized by discrepancy between subjective and objective assessments of sleep and is challenging to diagnosis and treat. Typically, polysomnographic (PSG) findings show significantly longer total sleep time than patients' report of sleep, and the difference between subjective and PSG sleep is greater than that seen in other insomnia subtypes. Subjective-objective sleep discrepancy may also present in different clinical pictures, as marked discrepancies between patients' perception of sleep and objective findings are common in a variety of medical, sleep and psychiatric disorders. However, there is a paucity of literature about the etiology and treatment of sleep discrepancy and paradoxical insomnia. Therefore, the underlying neurophysiological mechanisms of sleep discrepancy and paradoxical insomnia should be further investigated. Additionally, well-controlled clinical trials are needed to establish an evidence based intervention for treatment.

Insomnia and its impact on physical and mental health

In contrast to the association of insomnia with mental health, its association with physical health has remained largely unexplored until recently. Based on findings that insomnia with objective short sleep duration is associated with activation of both limbs of the stress system and other indices of physiological hyperarousal, which should adversely affect physical and mental health, we have recently demonstrated that this insomnia phenotype is associated with a significant risk of cardiometabolic and neurocognitive morbidity and mortality. In contrast, insomnia with normal sleep duration is associated with sleep misperception and cognitive-emotional arousal, but not with signs of physiological hyperarousal or cardiometabolic or neurocognitive morbidity. Interestingly, both insomnia phenotypes are associated with mental health, although most likely through different pathophysiological mechanisms. We propose that objective measures of sleep duration may become part of the routine evaluation and diagnosis of insomnia, and that these two insomnia phenotypes may respond differentially to biological versus psychological treatments.

Insomnia with Short Sleep Duration: Nosological, Diagnostic, and Treatment Implications

The diagnosis of insomnia is based solely on subjective complaints. This has contributed to the low reliability and validity of the current nosology of insomnia as well as to its lack of firm association with clinically relevant outcomes such as cardiometabolic and neurocognitive morbidity. We review evidence that insomnia with objective short sleep duration is associated with physiological hyperarousal, higher risk for hypertension, diabetes, neurocognitive impairment, and mortality as well as with a persistent course. It also appears that objective short sleep duration in poor sleepers is a biological marker of genetic predisposition to chronic insomnia. In contrast, insomnia with objective normal sleep duration is associated with cognitive-emotional and cortical arousal and sleep misperception but not with signs of physiological hyperarousal or medical complications. Thus, short sleep duration in insomnia may be a reliable marker of the biological severity and medical impact of the disorder. We propose that (a) objective measures of sleep be included in the diagnosis of insomnia and its subtypes, (b) objective measures of sleep obtained in the home environment of the patient would become part of the routine assessment and diagnosis of insomnia in a clinician's office setting, and (c) insomnia with short sleep duration may respond better to biological treatments, whereas insomnia with normal sleep duration may respond primarily to psychological therapies.

Insomnia with objective short sleep duration: the most biologically severe phenotype of the disorder

Until recently, the association of chronic insomnia with significant medical morbidity was not established and its diagnosis was based solely on subjective complaints. We present evidence that insomnia with objective short sleep duration is the most biologically severe phenotype of the disorder, as it is associated with cognitive-emotional and cortical arousal, activation of both limbs of the stress system, and a higher risk for hypertension, impaired heart rate variability, diabetes, neurocognitive impairment, and mortality. Also, it appears that objective short sleep duration is a biological marker of genetic predisposition to chronic insomnia. In contrast, insomnia with objective normal sleep duration is associated with cognitive-emotional and cortical arousal and sleep misperception but not with signs of activation of both limbs of the stress system or medical complications. Furthermore, the first phenotype is associated with unremitting course, whereas the latter is more likely to remit. We propose that short sleep duration in insomnia is a reliable marker of the biological severity and medical impact of the disorder. Objective measures of sleep obtained in the home environment of the patient would become part of the routine assessment of insomnia patients in a clinician's office setting. We speculate that insomnia with objective short sleep duration has primarily biological roots and may respond better to biological treatments, whereas insomnia with objective normal sleep duration has primarily psychological roots and may respond better to psychological interventions alone.

Comparative investigation of the psychophysiologic and idiopathic insomnia disorder phenotypes: psychologic characteristics, patients' perspectives, and implications for clinical management

STUDY OBJECTIVES

Insomnia is a common disorder, yet its proposed behavioral phenotypes are seldom differentiated. Two consecutive studies were designed to investigate psychologic characteristics and treatment preferences of people with idiopathic insomnia (IdI) relative to psychophysiologic insomnia (PI).

DESIGN

Cross-sectional, two-group comparison studies.

SETTING

Specialized sleep research center.

PARTICIPANTS

40 participants (29 female, mean age 46 yr) participated in study 1. An additional cohort of 61 adults (48 female, mean age 37 yr) participated in study 2. In total, samples comprised 51 participants with PI and 50 with IdI. All participants met diagnostic criteria for their respective insomnia phenotype.

INTERVENTIONS

N/A MEASUREMENTS AND RESULTS: Study 1 investigated sensitivity to arousal conditioning and sleep effort using self-report measures. Consistent with a model of conditioned arousal, participants with PI exhibited greater behavioral inhibition, i.e., sensitivity to threat and higher levels of sleep preoccupation. Study 2 investigated illness perceptions and cognitions and coping styles using self-report scales, and explored treatment acceptability based on the evaluation of 3 therapeutic scenarios. Results lend support to the hypothesis that IdI is considered somewhat more permanent than PI. Behavioral intervention was preferred to pharmacotherapy by both groups, and an acceptance treatment was considered more favorably by IdI study participants than by those with PI.

CONCLUSIONS

Many similarities between IdI and PI were observed across psychologic measures, and both groups exhibited a preference for behavioral treatment. However, their distinctive characteristics appear to suggest that an acceptance-based therapy may also be appropriate for some people with IdI.

(Mis)perception of sleep in insomnia: a puzzle and a resolution

Insomnia is prevalent, causing severe distress and impairment. This review focuses on illuminating the puzzling finding that many insomnia patients misperceive their sleep. They overestimate their sleep onset latency (SOL) and underestimate their total sleep time (TST), relative to objective measures. This tendency is ubiquitous (although not universal). Resolving this puzzle has clinical, theoretical, and public health importance. There are implications for assessment, definition, and treatment. Moreover, solving the puzzle creates an opportunity for real-world applications of theories from clinical, perceptual, and social psychology as well as neuroscience. Herein we evaluate 13 possible resolutions to the puzzle. Specifically, we consider the possible contribution, to misperception, of (1) features inherent to the context of sleep (e.g., darkness); (2) the definition of sleep onset, which may lack sensitivity for insomnia patients; (3) insomnia being an exaggerated sleep complaint; (4) psychological distress causing magnification; (5) a deficit in time estimation ability; (6) sleep being misperceived as wake; (7) worry and selective attention toward sleep-related threats; (8) a memory bias influenced by current symptoms and emotions, a confirmation bias/belief bias, or a recall bias linked to the intensity/recency of symptoms; (9) heightened physiological arousal; (10) elevated cortical arousal; (11) the presence of brief awakenings; (12) a fault in neuronal circuitry; and (13) there being 2 insomnia subtypes (one with and one without misperception). The best supported resolutions were misperception of sleep as wake, worry, and brief awakenings. A deficit in time estimation ability was not supported. We conclude by proposing several integrative solutions.

Moving beyond average values: assessing the night-to-night instability of sleep and arousal in DSM-IV-TR insomnia subtypes

STUDY OBJECTIVES

We explored differences between individuals with DSM-IV-TR diagnoses of primary insomnia (PI) and insomnia related to a mental disorder (IMD) by using serial measurements of self-reported sleep variables (sleep onset latency, SOL; wake after sleep onset, WASO; total sleep time, TST; sleep efficiency, SE), and visual analogue scale ratings of 2 forms of bedtime arousal (cognitive and emotional). Furthermore, we sought to examine the relationship between sleep and arousal within each diagnostic subgroup.

DESIGN

Between-group and within-group comparisons.

SETTING

Duke and Rush University Medical Centers, USA.

PARTICIPANTS

One hundred eighty-seven insomnia sufferers (126 women, average age 47.15 years) diagnosed by sleep specialists at 2 sleep centers as PI patients (n=126) and IMD patients (n=61).

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Multilevel models for sleep measures indicated that IMD displayed significantly more instability across nights in their TST (i.e., larger changes) than did PI patients. With respect to pre-sleep arousal, IMD patients exhibited higher mean levels of emotional arousal, as well as more instability on the nightly ratings of this measure. Within the PI group, correlational analyses revealed a moderate relationship between the 2 arousal variables and SOL (r values 0.29 and 0.26), whereas the corresponding correlations were negligible and statistically nonsignificant in the IMD group.

CONCLUSIONS

We found a number of differences on nighttime variables between those diagnosed with primary insomnia and those diagnosed with insomnia related to a mental disorder. These differences imply different perpetuating mechanisms involved in their ongoing sleep difficulties. Additionally, they support the categorical distinctiveness and the concurrent validity of these insomnia subtypes.

Sleep misperception and chronic insomnia in the general population: role of objective sleep duration and psychological profiles

OBJECTIVE

To examine the role of objective sleep duration, a novel marker in phenotyping insomnia, and psychological profiles on sleep misperception in a large, general population sample. Sleep misperception is considered by some investigators a common characteristic of chronic insomnia, whereas others propose it as a separate diagnosis. The frequency and the determinants of sleep misperception in general population samples are unknown.

METHODS

A total of 142 insomniacs and 724 controls selected from a general random sample of 1,741 individuals (aged ≥20 years) underwent a polysomnographic evaluation, completed the Minnesota Multiphasic Personality Inventory-2, and were split into two groups based on their objective sleep duration: "normal sleep duration" (≥6 hours) and "short sleep duration" (<6 hours).

RESULTS

The discrepancy between subjective and objective sleep duration was determined by two independent factors. Short sleepers reported more sleep than they objectively had, and insomniacs reported less sleep than controls with similar objective sleep duration. The additive effect of these two factors resulted in underestimation only in insomniacs with normal sleep duration. Insomniacs with normal sleep duration showed a Minnesota Multiphasic Personality Inventory-2 profile of high depression and anxiety and low ego strength, whereas insomniacs with short sleep duration showed a profile of a medical disorder.

CONCLUSIONS

Underestimation of sleep duration is prevalent among insomniacs with objective normal sleep duration. Anxious-ruminative traits and poor resources for coping with stress seem to mediate the underestimation of sleep duration. These data further support the validity and clinical utility of objective sleep measures in phenotyping insomnia.

A case of obstructive sleep apnea syndrome presenting as paradoxical insomnia

A 63-year-old female with obstructive sleep apnea syndrome (OSAS) presented with clinical features indistinguishable from paradoxical insomnia (PI). Her main complaint was chronic insomnia. Her subjective sleep latency was 2-3 h, subjective sleep time was less than 3 h, despite spending 8 h in bed, and she reported near constant awareness of her surroundings while lying in bed. Her body mass index (BMI) was 22.67 kg/m(2), and her neck circumference was 34.5 cm. Nocturnal polysomnography (NPSG) findings indicated severe OSAS. Her total sleep time (TST) was 359 min, sleep latency 13 min, and her apnea/hypopnea index (AHI) was 74.6/h. The aim of this report is to evaluate the association between PI and OSAS cases confirmed by NPSG.

Paradoxical insomnia: the role of CAP and arousals in sleep misperception

OBJECTIVE

The relationship between CAP parameters and subjective time perception during sleep in primary insomnia was investigated.

PATIENTS AND METHODS

Data collected from all-night PSG recordings of 20 patients with a diagnosis of paradoxical insomnia (misperceptors) were compared with those of 20 normal gender- and age-matched subjects (controls). Besides sleep staging, scoring measures included CAP parameters and EEG arousals.

RESULTS

Patients and controls presented non-significant differences in the amounts of objective sleep time (464 min vs. 447 min) and objective sleep latency (9 min vs. 8 min). Compared to controls, misperceptors reported a significantly shorter time of perceived sleep (285 min vs. 461 min) and a significantly longer duration of perceived sleep latency (51 min vs. 22 min). In spite of the 11 objective awakenings, misperceptors reported only 4 subjective awakenings, while controls described 2 of the 5 objective awakenings. Arousal index (31.7/h vs. 18.6/h) and total CAP rate (58.1% vs. 35.5%) were significantly higher in misperceptors. In the sleep period between objective and subjective sleep onset, CAP rate was 64.4% in misperceptors and 45.1% in controls (p<0.002). Insomniacs showed significantly higher amounts of CAP rate in stage 1 (62.7% vs. 37.5%) and in stage 2 (53.3% vs. 33.1%), but not in slow wave sleep. CAP phase A2 subtypes were significantly increased in misperceptors (31% vs. 24%).

CONCLUSIONS

The study points out the topical role of enhanced activation and arousal instability not only in the first part of the night (mismatch between objective and subjective sleep onset) but also in the misperception of consecutive objective awakenings which are subjectively grouped together as a single prolonged event.

Measuring the error in sleep estimation in normal subjects and in patients with insomnia

The aims of this study were to measure the error in sleep estimation in normal controls and subjects with primary insomnia to establish the minimum amount of sleep needed for reliable subjective estimation and to depict the distribution of the error in sleep estimation in both groups. A two-step retrospective (study 1) and prospective (study 2) validation study was carried out. Study 1 included 288 normal subjects [176 females and 112 males, mean age 58.5 years, standard deviation (SD) 7.23]. Study 2 included 159 patients (98 females and 61 males; mean age 49.1 years, SD 12.71) with primary insomnia. Participants underwent a full-night polysomnographic study, followed by a morning assessment of subjective sleep parameters. A misperception index (MI) was computed using the following formula: MI = [objective total sleep time (oTST)-subjective total sleep time (sTST)]/oTST. The statistical properties of this index were analysed in detail in both groups. In controls, the Bland-Altman test demonstrated the reliability of this index for values of oTST >120 min. Healthy subjects estimated their sleep time correctly, while insomniacs largely underestimated their sleep time. Statistical analysis of the distribution of MI in insomnia patients disclosed the presence of two subgroups, one with moderate sleep misperception (132 patients) and the other with high sleep misperception (27 patients). The latter presented MI values >or=0.9, exhibiting statistical properties different from those with MI <0.9 and from normal subjects. The MI gives a reliable and immediate description of sleep misperception in healthy and insomnia subjects. Its application supports the existence of the high misperception of insomnia as a separate pathological entity.

Effectiveness of a Multicomponent Group Treatment for Insomnia

The present study evaluates a multifaceted cognitive-behavioral group treatment in a routine clinical setting. The program consists of directly sleep related strategies such as sleep education, sleep restriction, stimulus control, relaxation, and cognitive restructuring. Also included are techniques that target illness maintaining factors such as stress-management, problem solving skills, and increase of activities. Twenty-eight physician-referred outpatients with chronic primary insomnia according to DSM-III-R criteria attended 11 weekly therapy-sessions. Results were obtained on a subjective and objective level using a sleep diary, questionnaires, and polysomnography, respectively. Pre- and post-treatment comparisons indicated significant changes on all main sleep diary variables, i.e. total sleep time, sleep efficiency, number of awakenings, sleep onset latency and wake after sleep onset, as well as for the global subjective sleep quality. Maximum improvement was reached after the more directly sleep-related part of the program. In addition, the intervention helped patients to reduce the amount and frequency of sleeping aids over time and improved their daytime-functioning. Subjective therapeutic gains were maintained at 3- and 12-month follow-ups. No significant treatment effects could be obtained on polysomnographic measures, taking into account that the baseline values were already in the normative range. After the intervention the patients were able to give a more realistic evaluation of their sleep. These results suggest that a multicomponent psychological treatment is beneficial for the improvement of sleep quality on a subjective level.

Positive sleep state misperception – A new concept of sleep misperception

OBJECTIVES

To better define the concept of sleep misperception and analyse a category of patients who overestimate their sleep. At present, a condition of underestimation of sleep is classified as paradoxical insomnia. Overestimation of sleep has also been reported in the past, with no clear reference to corresponding polysomnographic (PSG) findings or its clinical significance.

PATIENTS AND METHODS

Patients were recruited from the general population undergoing a PSG assessment for a cross-sectional retrospective study in a sleep clinic affiliated with a tertiary health center.

RESULTS

A group of patients who overestimated their sleep had mostly non-discriminating PSG findings when compared to patients who underestimated their sleep, and correct estimators. The only parameters that were significantly different were objective sleep duration and efficiency, and, importantly, respective multiple sleep latency test (MSLT) results. The patients who overestimated their sleep had a mean MSLT result of 7.8 min, which indicates moderate daytime sleepiness. Patients who underestimated their sleep and correct estimators had the respective MSLT results of >10 min, making a statistically significant difference.

CONCLUSION

The authors identified a condition opposite the previously described sleep underestimation, and named it 'positive sleep state misperception' (PSSM). The condition is characterised by a gross overestimation of sleep. Inadequate sleep results in a clinically significant excessive daytime sleepiness, which patients were not able to predict. The authors propose a new model that incorporates both ends of the sleep misperception spectrum.

Comparison of sleep condition and sleep-related psychological activity after cognitive-behavior and pharmacological therapy for chronic insomnia

BACKGROUND

Previous studies of insomnia focused mainly on the improvement of sleep condition and ignored the effects of sleep-related psychological activity and daytime function after pharmacological and behavioral treatments. We compared the clinical effects of both therapies on sleep condition, sleep-related psychological activity and daytime function in chronic insomnia.

METHODS

Seventy-one patients with chronic insomnia were randomly divided into 4 groups and either received cognitive-behavior therapy (CBT, n = 19), pharmacological therapy (PCT, n = 17), CBT plus medication (Combined, n = 18) or placebo (n = 17). The treatments lasted for 8 weeks with follow-ups conducted at 3 and 8 months. On the day after treatment ended, all patients were assessed using a polysomnogram (PSG), a sleep diary and a psychological assessment.

RESULTS

The three active treatments were more effective than placebo at the time the treatments were completed. Subjective sleep-onset latency, sleep efficacy and total sleep time were better in the PCT group than in the CBT group. At the 3-month follow-up, subjective and objective sleep-onset latency, sleep efficacy and total sleep time were better in the CBT group than in both the PCT and the Combined group. At the 8-month follow-up, the CBT group showed a steady comfortable sleep state, while the PCT and Combined groups were gradually returning to the pre-treatment condition. The Combined group showed a variable long-term effect. On the other hand, pre-sleep arousal at nighttime, dysfunctional beliefs about sleep as well as daytime functioning in the CBT group not only improved, but was better than in the other active treatment groups.

CONCLUSION

Medication and Combined therapy produced a short-term effect on chronic insomnia while CBT had a long-term effect of improved sleep-related psychological activity and daytime functioning.

Cognitive approaches to insomnia

Cognition is a broad term that refers to all mental activities and encompasses attention, perception, memory, reasoning, beliefs, attributions and expectations. The aim of the present paper is to draw together the major research findings relating to the importance of cognition in insomnia. Although the research to date has tended to focus on the role of unwanted intrusive thought (also known as worry or cognitive arousal), there is evidence that a broad range of cognitive processes are important for a full understanding of insomnia. These include beliefs, attributions, expectations, perception and attention. The treatment implications of this evidence are discussed, as are priorities for future research.

Subtyping primary insomnia: is sleep state misperception a distinct clinical entity?

Among the range of primary insomnia subtypes, those assigned such labels as subjective insomnia or sleep state misperception historically have been among the most intriguing yet challenging to understand and manage clinically. Such patients who produce seemingly normal polysomnograms often present rather compelling and, at times, dramatic sleep complaints. Our earliest formal sleep nosology included a separate diagnostic category for such individuals, but little research has been devoted to this insomnia subtype in the 20 years since this classification scheme was proposed. As a result, use of diagnoses such as subjective insomnia or sleep state misperception have remained controversial. The current article reviews this controversy and highlights the major criticisms forged against subdividing primary insomnia into objective and subjective subtypes. Subsequently, the relative merits of these criticisms are considered in view of early and recent findings vis-à-vis the subjective/objective insomnia dichotomy. Although available data are not conclusive, there appears to be sufficient evidence to suggest subjective and objective insomnia subtypes may suffer from distinctive forms of sleep-related pathophysiology. We conclude by advocating continued study of the subjective insomnia phenomenon and by providing specific directions for relevant future research.

Use of sleep hygiene in the treatment of insomnia

Sleep hygiene (SH) refers to a list of behaviors, environmental conditions, and other sleep-related factors that can be adjusted as a stand-alone treatment or component of multimodal treatment for patients with insomnia. This paper presents a review of SH, how this concept has been applied and often modified over the past 24 years, and how it relates to the modern sleep disorder nosology, particularly Inadequate Sleep Hygiene. Although a recognized and commonly utilized treatment option, there is no absolute consensus about which steps must be included to constitute SH treatment, and there is much overlap between SH and other cognitive-behavioral treatments for insomnia such as Stimulus Control Procedures and Sleep Restriction Therapy. The literature on the effects of manipulations of individual components of SH under experimental conditions (e.g. effects of presleep alcohol or caffeine intake) in normal sleepers show mixed results. Empirical data demonstrating the role of poor SH as a contributor to insomnia, or showing that good SH improves sleep in patients with insomnia, is not available. Instead of evaluating the impact of a comprehensive list of SH recommendations, a focus on guidelines for use of individual rules is needed.

A cognitive model of insomnia

Insomnia is one of the most prevalent psychological disorders, causing sufferers severe distress as well as social, interpersonal, and occupational impairment. Drawing on well-validated cognitive models of the anxiety disorders as well as on theoretical and empirical work highlighting the contribution of cognitive processes to insomnia, this paper presents a new cognitive model of the maintenance of insomnia. It is suggested that individuals who suffer from insomnia tend to be overly worried about their sleep and about the daytime consequences of not getting enough sleep. This excessive negatively toned cognitive activity triggers both autonomic arousal and emotional distress. It is proposed that this anxious state triggers selective attention towards and monitoring of internal and external sleep-related threat cues. Together, the anxious state and the attentional processes triggered by it tricks the individual into overestimating the extent of the perceived deficit in sleep and daytime performance. It is suggested that the excessive negatively toned cognitive activity will be fuelled if a sleep-related threat is detected or a deficit perceived. Counterproductive safety behaviours (including thought control, imagery control, emotional inhibition, and difficulty problem solving) and erroneous beliefs about sleep and the benefits of worry are highlighted as exacerbating factors. The unfortunate consequence of this sequence of events is that the excessive and escalating anxiety may culminate in a real deficit in sleep and daytime functioning. The literature providing preliminary support for the model is reviewed and the clinical implications and limitations discussed.

Cognitive behavioural interventions for sleep problems in adults aged 60+

BACKGROUND

The prevalence of sleep problems in adulthood increases with age. While not all sleep changes are pathological in later life, severe disturbances may lead to depression, cognitive impairments, deterioration of quality of life, significant stresses for carers and increased healthcare costs. The most common treatment for sleep disorders (particularly insomnia) is pharmacological. The efficacy of non-drug interventions has been suggested to be slower than pharmacological methods, but with no risk of drug-related tolerance or dependency. Cognitive and behavioural treatments for sleep problems aim to improve sleep by changing poor sleep habits, promoting better sleep hygiene practices and by challenging negative thoughts, attitudes and beliefs about sleep.

OBJECTIVES

To assess the efficacy of cognitive-behavioural interventions in improving sleep quality, duration and efficiency amongst older adults (aged 60 and above).

SEARCH STRATEGY

The following databases were searched: MEDLINE (1966 - October 2001); EMBASE (1980 - January 2002), CINAHL ( 1982 - January 2002; PsychINFO 1887 to 2002; The Cochrane Library (Issue 1, 2002); National Research Register (NRR [2002]). Bibliographies of existing reviews in the area, as well as of all trial reports obtained, were searched. Experts in the field were consulted.

SELECTION CRITERIA

Randomised controlled trials of cognitive behavioural treatments for primary insomnia where 80% or more of participants were over 60. Participants must have been screened to exclude those with dementia and/or depression.

DATA COLLECTION AND ANALYSIS

Abstracts of studies identified in searches of electronic databases were read and assessed to determine whether they might meet the inclusion criteria. Data were analysed separately depending on whether results had been obtained subjectively or objectively.

MAIN RESULTS

Six trials, including 282 participants with insomnia, examined the effectiveness of cognitive-behavioural treatments (CBT) for sleep problems in this population. The final total of participants included in the meta-analysis was 224. The data suggest a mild effect of CBT for sleep problems in older adults, best demonstrated for sleep maintenance insomnia.

REVIEWER'S CONCLUSIONS

When the possible side-effects of standard treatment (hypnotics) are considered, there is an argument to be made for clinical use of cognitive-behavioural treatments. Research is needed to establish the likely predictors of success with such treatments. As it may well be the case that the treatment efficacy of cognitive-behavioural therapy itself is not durable, the provision of "top-up" sessions of CBT training to improve durability of effect are worthy of investigation.

Chronic insomnia is associated with nyctohemeral activation of the hypothalamic-pituitary-adrenal axis: clinical implications

Although insomnia is, by far, the most commonly encountered sleep disorder in medical practice, our knowledge in regard to its neurobiology and medical significance is limited. Activation of the hypothalamic-pituitary-adrenal axis leads to arousal and sleeplessness in animals and humans; however, there is a paucity of data regarding the activity of the hypothalamic-pituitary-adrenal axis in insomniacs. We hypothesized that chronic insomnia is associated with increased plasma levels of ACTH and cortisol. Eleven young insomniacs (6 men and 5 women) and 13 healthy controls (9 men and 4 women) without sleep disturbances, matched for age and body mass index, were monitored in the sleep laboratory for 4 consecutive nights, whereas serial 24-h plasma measures of ACTH and cortisol were obtained during the fourth day. Insomniacs, compared with controls, slept poorly (significantly higher sleep latency and wake during baseline nights). The 24-h ACTH and cortisol secretions were significantly higher in insomniacs, compared with normal controls (4.2 +/- 0.3 vs. 3.3 +/- 0.3 pM, P = 0.04; and 218.0 +/- 11.0 vs. 190.4 +/- 8.3 nM, P = 0.07). Within the 24-h period, the greatest elevations were observed in the evening and first half of the night. Also, insomniacs with a high degree of objective sleep disturbance (% sleep time < 70), compared with those with a low degree of sleep disturbance, secreted a higher amount of cortisol. Pulsatile analysis revealed a significantly higher number of peaks per 24 h in insomniacs than in controls (P < 0.05), whereas cosinor analysis showed no differences in the temporal pattern of ACTH or cortisol secretion between insomniacs and controls. We conclude that insomnia is associated with an overall increase of ACTH and cortisol secretion, which, however, retains a normal circadian pattern. These findings are consistent with a disorder of central nervous system hyperarousal rather than one of sleep loss, which is usually associated with no change or decrease in cortisol secretion or a circadian disturbance. Chronic activation of the hypothalamic-pituitary-adrenal axis in insomnia suggests that insomniacs are at risk not only for mental disorders, i.e. chronic anxiety and depression, but also for significant medical morbidity associated with such activation. The therapeutic goal in insomnia should be to decrease the overall level of physiologic and emotional arousal, and not just to improve the nighttime sleep.

Insônia primária: diagnóstico diferencial e tratamento

A insônia primária é uma dissonia caracterizada pela dificuldade em iniciar e/ou manter o sono e pela sensação de não ter um sono reparador durante um período não inferior a 1 mês. Do ponto de vista polissonográfico, é acompanhada de alterações na indução, na continuidade e na estrutura do sono. Geralmente aparece no adulto jovem, é mais freqüente na mulher e tem um desenvolvimento crônico. A insônia primária é observada de 12,5% a 22,2% dos pacientes portadores de insônia crônica, sendo precedida em freqüência somente na insônia de depressão maior. A insônia primária crônica deve se diferenciar da insônia vinculada a uma higiene inadequada do sono, uma síndrome depressiva ou um transtorno de ansiedade generalizado. O tratamento da insônia primária inclui: higiene adequada do sono, terapia cognitiva e de conduta e uso de fármacos hipnóticos. Entre esses últimos, se destacam o zolpidem e a zopiclona, que melhoram significativamente o sono sem alterar sua estrutura ou induzir a uma reincidência da insônia logo após uma interrupção brusca. Além disso, o desenvolvimento de fármaco-dependência e de vício é muito pouco freqüente.

Subjective and psychophysiologic insomnia: an examination of sleep tendency and personality

The goal of this study was to compare insomniacs with and without objective verification, on the basis of sleep parameters, personality, and performance. An insomniac complaint group was subclassified as objective insomniac (OI) or subjective insomniac (SI) and compared to a non-complaint group. Groups did not differ on night sleep variables or daytime sleep latency measures; rather, a consistent sleep tendency was revealed for all three groups. The poorer the previous night sleep, the longer the daytime sleep latencies. Groups differed on subjective measures of conscious state during the day. SIs inaccurately estimated sleep/wake state in comparison to objective measures on the MSLT, whereas OIs were accurate in their estimations. Personality scores showed trends that suggested greater neuroticism for SIs and introversion for OIs. Results demonstrated subjective tendencies and related personality types that may help in the understanding of the complaint of insomnia with and without objective findings.