Validation of a French version of the Sleep Condition Indicator: a clinical screening tool for insomnia disorder according to DSM-5 criteria

The Sleep Condition Indicator (SCI): Psychometric properties of the European Portuguese version

Insomnia is a highly prevalent sleep disorder. It is the most frequent sleep complaint among Higher Education students. The Sleep Condition Indicator is a self-report tool aimed at assessing insomnia based on the DSM-5 criteria. The principal goal of this study was to establish preliminary psychometric properties of the European Portuguese version of the Sleep Condition Indicator in a sample of Higher Education students. Data from a diverse pool of Higher Education students (N = 537) were collected online over a month. Most participants were women (75%) and aged approximately 27 years. The Sleep Condition Indicator demonstrated good internal consistency (α = 0.85), with all the items accounting significantly for the scale reliability. The most appropriate factor structure considering the ordinal nature of the items was unidimensional, with all items explaining 64% of the total variance. However, a two-factor structure (sleep pattern and sleep-related impact) was also plausible when other statistical estimators were used. The Sleep Condition Indicator correlated significantly with insomnia severity, vulnerability to stress-related sleep disturbance, and self-reported daytime sleepiness. The optimal cut-off point established based on the receiver operating characteristic curve analysis was ≤ 16. A short version comprising only two items was also viable as suggested by the literature. The Sleep Condition Indicator is a reliable and valid tool for screening for insomnia. More studies with other groups are now required, specifically with clinical samples.

A longitudinal examination of the measurement properties and invariance of the Sleep Condition Indicator in Chinese healthcare students

BACKGROUND

The Sleep Condition Indicator (SCI), an insomnia measurement tool based on the updated Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria with sound psychometric properties when applied in various populations, was evaluated here among healthcare students longitudinally, to demonstrate its measurement properties and invariance in this particularly high-risk population.

METHODS

Healthcare students of a Chinese university were recruited into this two-wave longitudinal study, completing the simplified Chinese version of the SCI (SCI-SC), Chinese Regularity, Satisfaction, Alertness, Timing, Efficiency, Duration (RU_SATED-C) scale, Chinese Patient Health Questionnaire-4 (PHQ-4-C), and sociodemographic variables questionnaire (Q-SV) between September and November 2022. Structural validity, measurement invariance (MI), convergent and discriminant validity, internal consistency, and test-retest reliability of the SCI-SC were examined. Subgroups of gender, age, home location, part-time job, physical exercise, and stress-coping strategy were surveyed twice to test cross-sectional and longitudinal MI.

RESULTS

We identified 343 valid responses (62.9% female, mean age = 19.650 ± 1.414 years) with a time interval of seven days. The two-factor structure was considered satisfactory (comparative fit index = 0.953-0.989, Tucker-Lewis index = 0.931-0.984, root means square error of approximation = 0.040-0.092, standardized root mean square residual = 0.039-0.054), which mostly endorsed strict invariance except for part-time job subgroups, hence establishing longitudinal invariance. The SCI-SC presented acceptable convergent validity with the RU_SATED-C scale (r ≥ 0.500), discriminant validity with the PHQ-4-C (0.300 ≤ r < 0.500), internal consistency (Cronbach's alpha = 0.811-0.835, McDonald's omega = 0.805-0.832), and test-retest reliability (intraclass correlation coefficient = 0.829).

CONCLUSION

The SCI-SC is an appropriate screening instrument available for assessing insomnia symptoms among healthcare students, and the promising measurement properties provide additional evidence about validity and reliability for detecting insomnia in healthcare students.

Psychometric and structural properties of the traditional Chinese version of the sleep condition indicator for patients undergoing hemodialysis

PURPOSE

Insomnia is a prevalent sleep disorder among patients undergoing hemodialysis for chronic kidney disease. This study aimed to translate the sleep condition indicator (SCI), an insomnia screening tool based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), into a traditional Chinese version (SCI-TC) and evaluate the reliability and validity of this version for patients undergoing hemodialysis.

METHODS

This cross-sectional study conducted from November 2022 to June 2023 involved 200 patients on hemodialysis (mean age, 65.56 years; 61.5% men). Participants completed a series of questionnaires, with insomnia diagnosed according to DSM-5 criteria as the gold standard. A receiver operating characteristic (ROC) curve analysis was conducted to examine the sensitivity and specificity of the SCI-TC.

RESULTS

According to the DSM-5 criteria, 38% of the participants had insomnia. Cronbach's alpha for the SCI-TC was 0.92. The SCI-TC exhibited a good fit as a two-factor model, and its scores were significantly associated with those of the traditional Chinese versions of the Insomnia Severity Index, Patient Health Questionnaire-9, Generalized Anxiety Disorder-7, EuroQol 5-Dimensions scale, and EuroQol Visual Analogue Scale (r =  - 0.94, - 0.53, - 0.38, 0.27, and 0.30, respectively; all p < 0.05). The ROC curve analysis revealed an optimal cutoff of 16 points, with the sensitivity, specificity, and area under curve of 88.2%, 84.7%, and 0.91(95% confidence interval, 0.87-0.95), respectively.

CONCLUSION

The SCI-TC demonstrates robust reliability and validity in detecting insomnia among patients undergoing hemodialysis. These findings suggest that health-care providers should considering using the SCI as an easy-to-use tool for the timely detection of insomnia in this population.

Changes in sleep and the prevalence of probable insomnia in undergraduate university students over the course of the COVID-19 pandemic: findings from the U-Flourish cohort study

BACKGROUND

Sleep problems associated with poor mental health and academic outcomes may have been exacerbated by the COVID-19 pandemic.

AIMS

To describe sleep in undergraduate students during the COVID-19 pandemic.

METHOD

This longitudinal analysis included data from 9523 students over 4 years (2018-2022), associated with different pandemic phases. Students completed a biannual survey assessing risk factors, mental health symptoms and lifestyle, using validated measures. Sleep was assessed with the Sleep Condition Indicator (SCI-8). Propensity weights and multivariable log-binomial regressions were used to compare sleep in four successive first-year cohorts. Linear mixed-effects models were used to examine changes in sleep over academic semesters and years.

RESULTS

There was an overall decrease in average SCI-8 scores, indicating worsening sleep across academic years (average change -0.42 per year; P-trend < 0.001), and an increase in probable insomnia at university entry (range 18.1-29.7%; P-trend < 0.001) before and up to the peak of the pandemic. Sleep improved somewhat in autumn 2021, when restrictions loosened. Students commonly reported daytime sleep problems, including mood, energy, relationships (36-48%) and concentration, productivity, and daytime sleepiness (54-66%). There was a consistent pattern of worsening sleep over the academic year. Probable insomnia was associated with increased cannabis use and passive screen time, and reduced recreation and exercise.

CONCLUSIONS

Sleep difficulties are common and persistent in students, were amplified by the pandemic and worsen over the academic year. Given the importance of sleep for well-being and academic success, a preventive focus on sleep hygiene, healthy lifestyle and low-intensity sleep interventions seems justified.

Psychometric properties of Indonesian version of sleep condition indicator for screening poststroke insomnia

BACKGROUND

No study has examined the psychometric properties of the sleep condition indicator (SCI) for screening poststroke insomnia in the Indonesian population. We aimed to develop the Indonesian version of the sleep condition indicator (ISCI) and to examine its psychometric properties for screening adult patients in late sub-acute and chronic periods after stroke.

METHODS

This was a cross-sectional study with two stages. In the first stage, the English version of the SCI was translated into the ISCI using standard procedures. The psychometric properties of the ISCI were tested in the second stage. Internal consistency and test-retest reliability of ISCI were used to evaluate reliability. A confirmatory factor analysis (CFA) was performed to test construct validity. To test concurrent and convergent validity, the Indonesian version of the insomnia severity index (ISI-INA), generalized anxiety disorder questionnaire (IGAD-7), and patient health questionnaire (IPHQ-9) were used. A receiver operating characteristic (ROC) analysis was conducted to calculate the optimal cutoff score of the ISCI on the basis of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnostic criteria for insomnia.

RESULTS

A total of 160 adults with a diagnosis of stroke for more than 3 months were included (median age of 58.5 years, 31% met the DSM-5 criteria for insomnia). The ISCI had a satisfactory Cronbach's alpha of 0.89 and test-retest reliability of 0.78. The CFA revealed that the ISCI exhibited a satisfactory model fit and was associated with the ISI-INA, IGAD-7, and IPHQ-9 (r = -0.81, -0.32, and -0.52, respectively; all P < .001). The ROC test revealed that the optimal cutoff point of ≤23 yielded the highest sensitivity (94%) and specificity (97%).

CONCLUSION

The study results revealed that the 8-item ISCI is a reliable and valid screening tool for detecting insomnia symptoms according to the DSM-5 criteria in the chronic period after stroke.

Beliefs about sleep: links with ruminations, nightmare, and anxiety

OBJECTIVE

Dysfunctional cognitions related to sleep play a major role in insomnia but also in nightmares. Moreover, they are closely related to anxiety. To our knowledge, no study has probed the impact of non-constructive ruminations on these dimensions in their harmful interplay with sleep. The aim of this study is to provide new insights into the processes underlying the dysfunctional cognitions-insomnia relationship.

METHOD

Four hundred twenty nine French participants completed an anonymous online survey using Qualtrics® software. For the assessment of variables, we used the Mini Cambridge-Exeter Repetitive Thought Scale, the Nightmare Distress Questionnaire, the Beck Anxiety Inventory and the Sleep Condition Indicator. The frequency of nightmares was assessed subjectively via an item. Participants were divided into two groups according to their score on the insomnia assessment: good sleepers and poor sleepers.

RESULT

Anxiety was found to be a common mediator of the relationship between dysfunctional beliefs and attitudes toward sleep and insomnia between good (20.8%) and poor sleepers (24.6%). However, for poor sleepers, nightmare frequency (15.2%) and non-constructive ruminations (16.6%) emerged as mediators of this relationship.

CONCLUSION

The results gathered through this study bring interesting perspectives regarding the theoretical and etiological conceptualization of insomnia. We showed a positive association between dysfunctional beliefs and attitudes towards sleep and non-constructive ruminations in their contributory role to insomnia.

Psychological distress among hospital caregivers during and after the first wave of COVID-19: Individual factors involved in the severity of symptoms expression

Coronavirus disease 2019 has spread rapidly over the globe and has put an unprecedent psychological pressure on health care workers (HCWs). The present study aimed at quantifying the psychological consequences of the COVID-19 pandemic on HCWs during and after the first wave and identify sociodemographic, situational, and psychological risk/protective factors for symptoms severity. An online survey was sent by e-mail to all nurses and physicians employed by a teaching hospital in Brussels, Belgium. 542 (20,62%) completed the survey. 47%, 55%, 32% and 52% of participants reported posttraumatic stress, anxiety, depression and insomnia symptoms, respectively, during the peak. Two to three months later, posttraumatic symptoms emerged de novo in 54% of HCWs. It persisted in 89% of those presenting severe symptoms initially. Neuroticism was the strongest predictor of posttraumatic stress, anxiety, and insomnia. Work overload was the strongest predictor of depression and second predictor of posttraumatic stress, anxiety, and insomnia. Other significant predictors included being a nurse, the number of past traumatic experiences, avoidant coping style, and expressive suppression of emotions.

Attention-Deficit/Hyperactivity Disorder, Insomnia, and Sleepiness Symptoms among a Community Adult Sample: The Mediating Effect of Executive Behavioral Regulation and Metacognition Abilities

OBJECTIVE

Adult attention-deficit/hyperactivity disorder (ADHD) is characterized by a dysexecutive syndrome reflected in cognitive, emotional, and behavioral areas. Independently of a formal diagnosis of ADHD, higher ADHD symptoms are associated with higher levels of insomnia and sleepiness symptoms in adult population-based samples. Insomnia and sleepiness are sleep disorders that are both associated with deficits in several aspects of executive functions which in turn are likely to mimic a range of ADHD symptoms. Our objective was to explore the interrelationships between ADHD, insomnia, and sleepiness symptoms and executive functioning in community-dwelling adults.

METHOD

A total of 442 participants (18-89 years, 56% females) underwent a semistructured clinical interview and completed questionnaires for insomnia, sleepiness, and everyday behaviors in which executive functions are implicated. Mediation Models were applied.

RESULTS

Insomnia and sleepiness symptoms did not play a mediating role between ADHD symptoms and executive functioning. Conversely, our results highlighted a mediating effect of daytime insomnia consequences and sleepiness on ADHD symptoms via behavioral regulation executive symptoms (respectively, β = -0.32, p < .001, 95% CI [-0.46, -0.20]; β = 0.09, p < .05, 95% CI [0.02, 0.16]) and metacognitive executive symptoms (respectively, β = -0.30, p < .001, 95% CI [-0.44, -0.18]; β = 0.12, p < .01, 95% CI [0.04, 0.22]).

CONCLUSIONS

Daytime insomnia consequences and sleepiness symptoms could lead to ADHD-like symptoms through their associated executive symptoms expressed in daily life. When faced with symptoms suggestive of ADHD in adults, insomnia and sleepiness should be systematically screened with standardized instruments.

Non-Constructive Ruminations, Insomnia and Nightmares: Trio of Vulnerabilities to Suicide Risk

OBJECTIVE

Nightmare distress, nightmare frequency and anxiety are related to suicidal risk. Ruminations are a factor maximizing the risk of suicide. Research has identified two types of ruminations: constructive ruminations and non-constructive ruminations. As per our knowledge, no study has verified the links between non-constructive ruminations and sleep disorders and their role in the development of suicidal risk. We aimed to highlight the impact of non-constructive ruminations on nightmares, anxiety and insomnia in the development of suicidal risk.

METHODS

A total of 429 French participants responded to an anonymous online survey using the Qualtrics^® software. To assess variables, we used the Mini Cambridge-Exeter Repetitive Thought Scale, the Suicide Behaviors Questionnaire-Revised, the Nightmare Distress Questionnaire, the Beck Anxiety Inventory, and the Sleep Condition Indicator. Nightmare frequency was assessed by subjective evaluation through a question. We tested the possible effects of confounding variables such as age, gender, marital status and depression (Beck Depression Inventory-II).

RESULTS

Nightmare frequency was found to mediate the link between anxiety and suicidal risk (32.9%). Nightmare distress (37%) and non-constructive thoughts (48%) were also seen to mediate this link. Additionally, we found a moderating effect of insomnia on the link between non-constructive ruminations and suicidal risk (Z = 7.42, p < 0.001).

CONCLUSION

Our results showed that the frequency of nightmares, distress and non-constructive ruminations are closely related to suicidal risk. The interoperability between these elements and insomnia has thus been newly explored. The processes related to nightmares and suicidal risk as well as the underlying cognitive processes between sleep disorders and suicidal risk have been shed light upon.

Predictive Factors for Impaired Mental Health among Medical Students during the Early Stage of the COVID-19 Pandemic in Morocco

The COVID-19 pandemic has great consequences on mental health. We aimed to assess medical students’ psychological condition and influencing factors as a baseline evidence for interventions promoting their mental wellbeing. We conducted an online survey from April 8 to April 18, 2020 to examine the mental health of medical students by the nine-item Patient Health Questionnaire, seven-item Generalized Anxiety Disorder Scale, seven-item Insomnia Severity Index, and six-item Kessler psychological distress scale. Factors associated with mental health outcomes were identified by multivariable logistic regression analysis. Five hundred forty-nine students completed the survey; 341 (62.3%), 410 (74.6%), 344 (62.6%), and 379 (69%) reported anxiety, depression, insomnia, and distress, respectively. Female students, living in high COVID-19 prevalence locations, more than 25 days confinement, psychiatric consult history, and being in a preclinical level of studies had higher median scores and severe symptom levels. Multivariable logistic regression showed female gender as a risk factor for severe symptoms of anxiety (odds ratio [OR]: 1.653; 95% CI: 1.020–2.679; P = 0.042), depression (OR: 2.167; 95% CI: 1.435–3.271; P < 0.001), insomnia (OR: 1.830; 95% CI: 1.176–2.847; P = 0.007), and distress (OR: 1.994; 95% CI: 1.338–2.972; P = 0.001); preclinical level of enrollment as a risk factor for depression (OR: 0.679; 95% CI: 0.521–0.885; P = 0.004), insomnia (OR: 0.720; 95% CI: 0.545–0.949; P = 0.02), and distress (OR: 0.650; 95% CI: 0.499–0.847; P = 0.001), whereas living in high COVID-19 prevalence locations was a risk factor for severe anxiety (OR: 1.628; 95% CI: 1.090–2.432; P = 0.017) and depression (OR: 1.438; 95% CI: 1.002–2.097; P = 0.05). Currently, medical students experience high levels of mental health symptoms, especially female students, those at a preclinical level and living in regions with a high prevalence of COVID-19 cases. Screening for mental health issues, psychological support, and long-term follow-up could alleviate the burden and protect future physicians.

Validation of insomnia questionnaires in the general population: The Nord-Trøndelag Health Study (HUNT)

The primary aim was to validate questionnaire-based insomnia diagnoses from a modified Karolinska Sleep Questionnaire (KSQ) and the Insomnia Severity Index (ISI), by age category (< or >65 years), against a semi-structured face-to-face interview. Secondary aims were to split validity by diagnostic certainty of the interview and to compare prevalence estimates of questionnaire- and interview-based diagnoses. A total of 232 out of 1,200 invited (19.3%) from the fourth Nord-Trøndelag Health Study (HUNT4) completed questionnaires, including the KSQ and ISI, shortly before attending a face-to-face diagnostic interview for insomnia based on the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). Both a tentative (DSM-5 criteria A-E) and a definite (criteria A-H) interview diagnosis was evaluated. Cohen's kappa statistic quantified questionnaire validity. In all, 33% (95% confidence interval 27-39%) of participants had definite insomnia: 40% of women and 21% of men. The ISI (cut-off 12) and several KSQ-based diagnoses showed very good validity (κ ≤0.74) against the tentative, versus good validity (κ ≤0.61) against the definite interview diagnosis. Short questionnaires, requiring a daytime symptom at least three times a week, may underestimate insomnia prevalence. Validity was consistently higher for persons aged below versus above 65 years (definite insomnia: κ ≤0.64 vs. κ ≤0.56). Our results have implications for epidemiological population-based studies utilising insomnia questionnaires.

Assessment of the efficacy of a fatigue management therapy in schizophrenia: study protocol for a randomized, controlled multi-centered study (ENERGY)

Background

Fatigue is a well-known common clinical feature of numerous chronic diseases including various forms of cancer, neurological disorders such as multiple sclerosis, and psychiatric disorders. A significant proportion of people with schizophrenia (30–60%) reportedly experience fatigue, which impacts negatively on participation in various activities, including work, study, leisure, and social pursuits. Causes of fatigue in schizophrenia are poorly understood and there are no established treatments. Several evidence-based interventions for fatigue syndrome including psychoeducation, cognitive behavioral therapy, and graded exercise therapy have been shown to be effective in other medical conditions and could be adapted to address fatigue in schizophrenia patients. As there are no psychosocial or pharmacological interventions with proved efficacy for fatigue in schizophrenia, there is an urgent need for the development of strategies to improve fatigue management in schizophrenia.

The aim of this project is to evaluate in a single blind randomized clinical trial the efficacy of a cognitive-behavioral therapy (CBT) intervention compared to treatment as usual (TAU) on fatigue as the main outcome in schizophrenia patients. Clinical symptoms, physical functioning, major cognitive functions, quality of life and functioning, treatment dosage, daily motor activity, biological markers with inflammatory markers are also considered as secondary outcomes.

Methods/design

Two hundred patients meeting the inclusion criteria will be randomized to either of the study arms (intervention or TAU). The ENERGY intervention will be delivered according to a standardized treatment manual comprising six modules addressing fatigue and sleep over 14 individual therapy sessions. The treatment encompasses core CBT principles of psycho-education, behavioral activation, behavioral experiments, cognitive restructuring, problem-solving, and relapse prevention. Sessions will follow the traditional CBT structure of agenda setting, review of homework tasks, and introduction of a new concept/technique with collaborative discussions on how to implement such strategies in the participant’s day-to-day environment. Our primary endpoint will be the severity of fatigue assessed at baseline and at the 9-month follow-up using the “Multidimensional Fatigue Inventory” (MFI).

Discussion

The trial will provide the first test of CBT intervention for fatigue for patients with schizophrenia. This study will also test to what extent the treatment can be implemented in everyday practice.

Trial registration

ClinicalTrials.govNCT04332601. Registered on 10 April 2020.

Advanced psychometric testing on a clinical screening tool to evaluate insomnia: sleep condition indicator in patients with advanced cancer

Purpose

To examine the psychometric properties of the Sleep Condition Indicator (SCI) using different psychometric approaches [including classical test theory, Rasch models, and receiver operating characteristics (ROC) curve] among patients with advanced cancer.

Methods

Through convenience sampling, patients with cancer at stage III or IV (n = 859; 511 males; mean ± SD age = 67.4 ± 7.5 years) were recruited from several oncology units of university hospitals in Iran. All the participants completed the SCI, Insomnia Severity Index (ISI), Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), Hospital Anxiety and Depression Scale (HADS), General Health Questionnaire (GHQ), and Edmonton Symptom Assessment Scale (ESAS). In addition, 491 participants wore an actigraph device to capture objective sleep.

Results

Classical test theory [factor loadings from confirmatory factor analysis = 0.76–0.89; test–retest reliability = 0.80–0.93] and Rasch analysis [infit mean square (MnSq) = 0.63–1.31; outfit MnSq = 0.61–1.23] both support the construct validity of the SCI. The SCI had significant associations with ISI, PSQI, ESS, HADS, GHQ, and ESAS. In addition, the SCI has satisfactory area under ROC curve (0.92) when comparing a gold standard of insomnia diagnosis. Significant differences in the actigraphy measure were found between insomniacs and non-insomniacs based on the SCI score defined by ROC.

Conclusion

With the promising psychometric properties shown in the SCI, healthcare providers can use this simple assessment tool to target the patients with advanced cancer who are at risk of insomnia and subsequently provide personalized care efficiently.

Assessing Sleep-Related Safety Behaviors: Adaptation and Validation of a French Version of the Sleep-Related Behaviors Questionnaire in a Nonclinical Sample

Objective/Background: Safety behaviors play a prominent role in the development and maintenance of insomnia. The Sleep-Related Behaviors Questionnaire (SRBQ) is a self-report questionnaire designed to assess safety behaviors employed to cope with fatigue or to improve sleep. Despite its frequent use in insomnia, no systematic psychometric validation of the SRBQ has been conducted; its factor structure has never been explored. Furthermore, there is no French version of this scale. The goal of this study was to empirically validate a French version of the SRBQ. Participants/Methods: A total of 539 French-speaking community-dwelling participants from the general population completed a face-to-face clinical interview to determine insomnia disorder against DSM-5 criteria and several questionnaires including the French SRBQ. Results: SRBQ items with poor psychometric properties were removed, thus leading to a 20-item version (SRBQ-20). Exploratory factor analysis and parallel analysis revealed three distinct factors with good internal consistency. The results supported the internal temporal stability of the SRBQ-20. The construct validity of that instrument was underpinned by correlations obtained with various measures of insomnia and related constructs. Adequate discriminative validity was established by comparing individuals with insomnia and individuals without insomnia. Conclusions: This study demonstrated that the French version of the SRBQ-20 has good psychometric properties.

Presleep Cognitive Arousal and Insomnia Comorbid to Parkinson Disease: Evidence for a Serial Mediation Model of Sleep-Related Safety Behaviors and Dysfunctional Beliefs About Sleep

STUDY OBJECTIVES

Insomnia disorder (ID) is highly associated with Parkinson disease (PD) with great negative effect on health-related quality of life. Nonetheless, the relevance of psychological processes involved in the maintenance of insomnia is yet to be established in the context of this neurological condition. Our aim was to examine a serial meditation model of sleep-related safety behaviors and dysfunctional beliefs about sleep in association with presleep cognitive arousal and ID in patients with PD.

METHODS

A total of 68 patients with PD completed self-report measures including the Sleep-Related Behaviors Questionnaire (SRBQ-20), Dysfunctional Beliefs and Attitudes about Sleep (DBAS-16), and the cognitive subscale of the Presleep Arousal Scale (PSAS-C). ID was assessed according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria. Bootstrapped serial mediation analyses were conducted to test indirect effects.

RESULTS

Overall, 55.6% of patients with PD met diagnostic criteria for ID. The association between presleep cognitive arousal (PSAS-C) and ID was serially mediated by sleep-related safety behaviors (SRBQ-20) and strong endorsement of dysfunctional beliefs about sleep (DBAS-16) (bias-corrected 95% confidence interval for the indirect effect = 0.013, 0.093). An alternate serial mediation model in which dysfunctional beliefs about sleep precede sleep-related safety behaviors was not statistically significant (bias-corrected 95% confidence interval for the indirect effect = -0.001, 0.046).

CONCLUSIONS

ID comorbid to PD is associated with the classic psychological factors perpetuating ID in neurological disease-free individuals with insomnia. Target-oriented interventions for instance cognitive behavioral therapy for chronic insomnia should be considered as a treatment approach for ID comorbid to PD.

CITATION

Lebrun C, Gély-Nargeot M-C, Maudarbocus KH, Rossignol A, Geny C, Bayard S. Presleep cognitive arousal and insomnia comorbid to parkinson disease: evidence for a serial mediation model of sleep-related safety behaviors and dysfunctional beliefs about sleep. J Clin Sleep Med. 2019;15(9):1217-1224.

A classical test theory evaluation of the Sleep Condition Indicator accounting for the ordinal nature of item response data

Background

Insomnia symptoms are common among young adults and affect about 5% to 26% of 19 to 34-year-olds. In addition, insomnia is associated with poor mental health and may affect daily performance. In research, as well as in clinical practice, sleep questionnaires are used to screen for and diagnose insomnia. However, most questionnaires are not developed according to current DSM-5 diagnostic criteria. An exception is the recently developed Sleep Condition Indicator (SCI), an eight-item scale screening for insomnia.

Aim

The aim of this study was to perform a Classical Test Theory (CTT) based psychometric evaluation of the SCI in a sample of Swedish university students, by taking the ordinal nature of item level data into account.

Methods

The SCI was translated into Swedish and distributed online to undergraduate students at three Swedish universities, within programs of health, psychology, science or economy. Of 3673 invited students, 634 (mean age 26.9 years; SD = 7.4) completed the questionnaire that, in addition to the SCI, comprised other scales on sleep, stress, lifestyle and students’ study environment. Data were analyzed according to CTT investigating data completeness, item homogeneity and unidimensionality.

Results

Polychoric based explorative factor analysis suggested unidimensionality of the SCI, and internal consistency was good (Cronbach’s alpha, 0.91; ordinal alpha, 0.94). SCI scores correlated with the Insomnia Severity Index (-0.88) as well as with sleep quality (-0.85) and perceived stress (-0.50), supporting external construct validity.

Conclusions

These observations support the integrity of the of the SCI. The SCI demonstrates sound CTT-based psychometric properties, supporting its use as an insomnia screening tool.

The Sleep Condition Indicator: reference values derived from a sample of 200 000 adults

The Sleep Condition Indicator (SCI) is an eight-item rating scale that was developed to screen for insomnia disorder based on DSM-5 criteria. It has been shown previously to have good psychometric properties among several language translations. We developed age- and sex-referenced values for the SCI to assist the evaluation of insomnia in everyday clinical practice. A random sample of 200 000 individuals (58% women, mean age: 31 ± 13 years) was selected from those who had completed the SCI via several internet platforms. Descriptive and inferential methods were applied to generate reference data and indices of reliable change for the SCI for men and women across the age deciles 16-25, 26-35, 36-45, 46-55, 56-65 and 66-75 years. The mean SCI score for the full sample was 14.97 ± 5.93. Overall, women scored worse than men (14.29 ± 5.83 versus 15.90 ± 5.94; mean difference: -1.60, η²  = 0.018, Cohen's d = 0.272) and those of older age scored worse than those younger (-0.057 points per year, 95% confidence interval (CI): -0.059 to -0.055) relative to age 16-25 years. The Reliable Change Index was established at seven scale points. In conclusion, the SCI is a useful instrument for clinicians and researchers that can help them to screen for insomnia, compare completers to individuals of similar age and sex and establish whether a reliable change was achieved following treatment.