Self-reported seasonality is associated with complaints of sleep problems and deficient sleep duration: the Hordaland Health Study

Seasonal patterns in Chinese population: Validating the seasonal pattern assessment questionnaire and exploring associations with psychiatric diagnoses and biological rhythms

Seasonal patterns (SP) exert a notable influence on the course and prognosis of patients with affective disorders, serving as a specifier in diagnosis. However, there is limited exploration of seasonality among psychotic patients, and the distinctions in seasonality among psychiatric patients remain unclear. In this study, we enrolled 198 psychiatric patients with anxiety and depressive disorders (A&D), bipolar disorder (BD), and schizophrenia (SZ), as well as healthy college students. Online questionnaires, including the Seasonal Pattern Assessment Questionnaire (SPAQ) for seasonality, the Morningness and Eveningness Questionnaire-5 (MEQ-5) for chronotypes, and the Pittsburgh Sleep Quality Index (PSQI), were administered. The validity and reliability of the Chinese version of the SPAQ were thoroughly analyzed, revealing a Cronbach's alpha of 0.896 with a two-factor structure. Results indicated that higher seasonality was correlated with poorer sleep quality and a more delayed chronotype (p < 0.05). Significant monthly variations were particularly evident in BD, specifically in mood, appetite, weight, social activities, and sleep dimensions (p < 0.001). In summary, the Chinese version of SPAQ is validated, demonstrating moderate correlations between seasonality, chronotype, and sleep quality. BD patients exhibited the strongest seasonality, while mood disorder patients displayed more delayed chronotypes than SZ.

Seasonal affective disorder and engagement in physical activities among adults in Alaska

Seasonal affective disorder (SAD) is a type of depression in which symptoms occur during a particular season. While physical activity has been shown to improve symptoms for depression in general populations, the relationships between physical activity and experiences of seasonality and SAD remain underexplored. We conducted a survey with adult members of a recreational gym in Fairbanks, Alaska. The survey collected self-report data on sociodemographics, health behaviours, and elements of the Seasonal Pattern Assessment Questionnaire (SPAQ). Results indicate that 18.68% of our study participants meet the criteria for winter-pattern SAD and 43.96% meet the criteria for subsyndromal SAD ("winter blues"). We conducted two regressions to understand experiences of SAD and predictors of seasonality more generally. Gender was a significant predictor of SAD, with women more likely than men to experience SAD (p = .04). Being social at the gym, whether going to the gym with others or participating in activities with others, was associated with higher seasonality than being independent at the gym (p = .03). Younger age was also associated with higher seasonality (p < .001). This study contributes new insights about the relationship between engagement in physical activities and experiences of seasonality among adults in a northern latitude.

Self-reported seasonality is strongly associated with chronotype and weakly associated with latitude

The aim of this study was to investigate the association between self-reported seasonality, i.e., seasonal variations in mood and related behavior, and chronotype, and between self-reported seasonality and home address' latitude. Data were collected from an online questionnaire with 45,338 participants. Seasonality and chronotype were measured with the Global Seasonality Score (GSS) and the Composite Scale of Morningness, respectively. The participants were categorized into extreme morning types, moderate morning types, intermediate types, moderate evening types, and extreme evening types. Furthermore, participants were categorized depending on home address' latitude. Data were analyzed with chi-square tests and logistic regression analyses adjusting for sex, age, marital status, level of education, and children living at home. Results showed that high seasonality (GSS 11+) was found in 20.9%. The prevalence dose-dependency ranged from 12.2% in extreme morning types to 42.6% in extreme evening types (adjusted OR = 4.21, CI = 3.27-5.41). The prevalence was higher in participants living in North-Norway (latitude from 65 to 71⁰N) versus South-Norway (latitude from 58 to 65⁰N) (23.8% versus 20.7%; adjusted OR = 1.18, CI = 1.08-1.28). When comparing the northernmost (69-71⁰N) to the southernmost (58-59⁰N) counties of Norway, the association was stronger (24.9% versus 18.7%; adjusted OR = 1.37, CI = 1.20-1.56). Among the adjusting variables, high seasonality was associated with female sex, younger age, being unmarried, low level of education, and not having children living at home. In conclusion, about one in five Norwegians reported high seasonality. High seasonality was strongly associated with late chronotype (being an evening type) and weakly associated with living in the north (high latitude).

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.

Seasonality in pain, sleep and mental distress in patients with chronic musculoskeletal pain at latitude 69° N

Seasonality is evident in several aspects of human health and behavior, whereas seasonality in chronic pain is less well studied. We examined seasonal variation in pain severity and pain dissemination, as well as in pain-associated conditions, such as sleep impairment, sleep timing, mental distress, fatigue and physical activity. We also examined if any of these associated conditions moderated the seasonality in pain. This prospective study was conducted in the subarctic municipality of Tromsø, Norway (69º North), on a sample of patients with chronic musculoskeletal pain (N = 56). Data were collected with self-report questionnaires and objective actigraphy measures (7 days) twice: winter and summer. Mixed linear regression models were fitted. A modest seasonality effect was observed in pain severity (highest in summer), but not in pain dissemination. Seasonality with increased physical activity and delayed sleep timing in the summer was also present. The remaining pain-associated self-report or objective measures indicated no seasonality. The season-pain association was not significantly moderated by any of the pain-associated conditions. Previous studies on healthy individuals residing in polar areas have suggested an opposite seasonal effect with delay of the sleep-wake rhythm in winter. Our results based on a clinical sample thus represent a novel finding that needs to be examined further with regard to seasonal circadian entrainment and alignment in pain populations. These results may have clinical value for the treatment of patients with musculoskeletal pain as seasonality may require seasonal adjustments of pain treatment strategies.

Occupational balance and sleep among women

BACKGROUND

In occupational therapy, while several studies have focussed on occupational balance, few have investigated it in the context of sleep.

AIMS

The aim of this study was to investigate the associations between sleep and occupational balance among women.

MATERIAL AND METHODS

In total, 157 women responded to the Occupational Balance Questionnaire and Karolinska Sleep Questionnaire. Linear regression was used to analyse data.

RESULTS

The median score for occupational balance was 12 (interquartile range [IQR] 9), while that for sleep was 86 (IQR 16). Sleep and sleepiness fatigue were significantly associated (p < 0.1) with satisfaction with the number of occupations during a regular week. Difficulties awakening and snoring disorders were significantly associated (p < 0.1) with balance with physical, social, intellectual, and restful occupations.

CONCLUSIONS

The majority of participants slept well and had a good sleep quality. There is an association between occupational balance and sleep. In particular, aspects related to the number of occupations, adequate time to perform them and the time spent recovering and sleeping were associated with good sleep quality. Balance among physical, social, intellectual, and restful occupations was associated with difficulties awakening and snoring.

SIGNIFICANCE

Our results support the need for occupational therapists to focus on occupational balance, to improve women's sleep.

Effects of Cognitive Behavioral Therapy on Eating Behaviors, Affective Symptoms, and Weight Loss After Bariatric Surgery: a Randomized Clinical Trial

Background

The long-term effects of presurgical psychological interventions on weight loss, eating behaviors, affective symptoms, and health-related quality of life remain uncertain. This study aimed to assess the 4-year effects of cognitive behavioral therapy (CBT) before bariatric surgery on these outcomes.

Methods

Single-center randomized controlled parallel-group trial. Patients were assessed after CBT before bariatric surgery (n = 98) and 1 year (n = 80) and 4 years (n = 61) after surgery. The intervention group received a 10-week preoperative individual CBT focusing on self-monitoring to identify triggers of dysfunctional eating behaviors in order to improve regulation of eating as well as the breaking of the interrelationship between eating behaviors, negative mood, and dysfunctional cognitions.

Results

The 61 patients (70% women) had a mean (SD) age of 42.4 (10.1) years and BMI 43.5 (4.4) kg/m². Preoperative CBT was not associated with 1- and 4-year reduction of dysfunctional eating behaviors, affective symptoms and body weight, or improved health-related quality of life. Patients with minor or considerable symptoms of depression receiving CBT had lower mean BMI than controls, both before surgery, − 1.1 kg/m², and − 1.5 kg/m², and 4-years after surgery, − 2.9 kg/m² and − 7.5 kg/m², respectively.

Conclusion

Presurgical CBT was not associated with better long-term outcomes. However, in patients with minor or considerable symptoms of depression, CBT was associated with lower body weight before and 4 years after surgery. Additional studies are required to verify whether patients with symptoms of depression should be offered CBT before and/or after bariatric surgery, and which clinical aspects the CBT should address.

Trial Registration

Clinicaltrials.gov Identifier: NCT01403558.

Sleep in seasonal affective disorder

Sleep in seasonal affective disorder (SAD) has been primarily characterized by delayed sleep timing and self-reports of hypersomnolence. It is unclear whether delayed sleep timing is due to circadian or behavioral misalignment and if effective treatments operate independently of the circadian system. Discrepancies between self-report and actigraphic/polysomnographic sleep duration in SAD hinder clarification of hypersomnolence as a cardinal symptom. Previous studies have largely neglected the summer remission period in SAD, which could yield valuable insight to the role sleep disturbances play in the onset and recurrence of winter depressive episodes. Future studies should incorporate multi-method, multi-season assessment of sleep and circadian rhythms to best characterize relevant sleep-circadian phenotypes. Empirically determining sleep phenotypes present in SAD will pave the way for targeted sleep interventions.

Differences in sleep functioning between individuals with seasonal affective disorder and major depressive disorder in Finland

BACKGROUND

Sleep problems are commonly reported in seasonal affective disorder (SAD) and major depressive disorder (MDD). However, the specific characteristics of sleep difficulties differ. Frequent sleep problems in MDD are insomnia and night awakenings, whereas SAD patients complain of hypersomnia and daytime sleepiness. No previous studies have reported differences in sleep functioning between these two disorders.

METHODS

We interviewed 4554 subjects from the Health 2011 survey and included 4153 individuals in this study. We selected participants who fulfilled the criteria for SAD (n = 223), nonseasonal-MDD (n = 238), SAD + MDD (n = 65), and controls (n = 3627). They completed the World Health Organization Composite International Diagnostic Interview, Munich version (M-CIDI), the Seasonal Pattern Assessment Questionnaire (SPAQ), The Beck Depression Inventory (BDI), the EuroQoL (EQ-5), the Alcohol Use Disorders Identification Test (AUDIT) and several questions about sleeping, based on the Basic Nordic Sleep Questionnaire (BNSQ).

RESULTS

We found Significant differences between groups for "enough sleep", "breathing interruptions during sleep", "tiredness during the day", and "sleeping difficulties". Controls reported better functioning in all sleep variables. SAD + MDD individuals showed more problems in "enough sleep" than SAD, more "breathing interruptions during sleep" than SAD and nonseasonal-MDD, felt more "tired during the day" than SAD and nonseasonal-MDD, and reported more "sleeping difficulties" than SAD and nonseasonal-MDD. Finally, nonseasonal-MDD individuals felt more "tired during the day" than SAD.

CONCLUSION

Individuals with SAD + MDD show generalized sleeping problems. However, when SAD and nonseasonal-MDD appear separately, similar sleep functioning is observed. Nonseasonal-MDD subjects report to be more tired during the day than SAD.

The effects of seasonal affective disorder and alcohol abuse on sleep and snoring functions in a population-based study in Finland

Seasonal affective disorder (SAD) is a recurrent depressive disorder with a seasonal pattern. In addition to some specific symptoms such as sad mood, low energy or carbohydrate craving, this mood disorder is also characterized by the presence of sleeping problems and alcohol disorders. Interestingly, there is a strong link between alcohol use and sleeping deficits. Although previous studies have focused extensively on the sleep patterns in SAD patients and patients with alcohol use disorder (AUD), no research has yet been conducted on subjects with comorbid SAD and AUD. The aim of this study was to examine the differences in sleep functioning between subjects with SAD, AUD and SAD+AUD. A total of 4554 Finnish subjects from the population-based Health 2011 survey were interviewed, and of these 2430 individuals completed all the questionnaires. We selected those participants who fulfilled the criteria for SAD (n = 298), AUD (n = 359), SAD+AUD (n = 69), controls 1 (no current alcohol use, n = 226) and controls 2 (current alcohol use but not AUD, n = 1445). Controls with a history of alcohol abuse were excluded (n = 33). All the participants completed the EuroQoL five-dimensions questionnaire (EQ-5), the Seasonal Pattern Assessment Questionnaire (SPAQ), the Alcohol Use Disorders Identification Test (AUDIT) and several questions about sleeping, based on the Basic Nordic Sleep Questionnaire (BNSQ). Our results showed that those subjects with SAD+AUD reported the highest levels of subjective sleeping problems compared to controls, SAD and AUD. These findings suggest the relevance of examining the comorbidity of SAD and AUD when studying sleep functioning in these groups of patients.

Retrospectively reported month-to-month variation in sleeping problems of people naturally exposed to high-amplitude annual variation in daylength and/or temperature

Compared to literature on seasonal variation in mood and well-being, reports on seasonality of trouble sleeping are scarce and contradictive. To extend geography of such reports on example of people naturally exposed to high-amplitude annual variation in daylength and/or temperature. Participants were the residents of Turkmenia, West Siberia, South and North Yakutia, Chukotka, and Alaska. Health and sleep-wake adaptabilities, month-to-month variation in sleeping problems, well-being and behaviors were self-assessed. More than a half of 2398 respondents acknowledged seasonality of sleeping problems. Four of the assessed sleeping problems demonstrated three different patterns of seasonal variation. Rate of the problems significantly increased in winter months with long nights and cold days (daytime sleepiness and difficulties falling and staying asleep) as well as in summer months with either long days (premature awakening and difficulties falling and staying asleep) or hot nights and days (all 4 sleeping problems). Individual differences between respondents in pattern and level of seasonality of sleeping problems were significantly associated with differences in several other domains of individual variation, such as gender, age, ethnicity, physical health, morning-evening preference, sleep quality, and adaptability of the sleep-wake cycle. These results have practical relevance to understanding of the roles playing by natural environmental factors in seasonality of sleeping problems as well as to research on prevalence of sleep disorders and methods of their prevention and treatment in regions with large seasonal differences in temperature and daylength.

ADHD, circadian rhythms and seasonality

OBJECTIVE

We evaluated whether the association between Adult Attention-Deficit/Hyperactivity Disorder (ADHD) and Seasonal Affective Disorder (SAD) was mediated by the circadian rhythm.

METHOD

Data of 2239 persons from the Netherlands Study of Depression and Anxiety (NESDA) were used. Two groups were compared: with clinically significant ADHD symptoms (N = 175) and with No ADHD symptoms (N = 2064). Sleep parameters were sleep-onset and offset times, mid sleep and sleep duration from the Munich Chronotype Questionnaire. We identified the prevalence of probable SAD and subsyndromal SAD using the Seasonal Pattern Assessment Questionnaire (SPAQ). Clinically significant ADHD symptoms were identified by using a T score>65 on the Conners Adult ADHD Rating Scale.

RESULTS

The prevalence of probable SAD was estimated at 9.9% in the ADHD group (vs. 3.3% in the No ADHD group) and of probable s-SAD at 12.5% in the ADHD group (vs 4.6% in the No ADHD group). Regression analyses showed consistently significant associations between ADHD symptoms and probable SAD, even after adjustment for current depression and anxiety, age, sex, education, use of antidepressants and benzodiazepines (B = 1.81, p < 0.001). Late self-reported sleep onset was an important mediator in the significant relationship between ADHD symptoms and probable SAD, even after correction for confounders (total model effects: B = 0.14, p ≤ 0.001).

CONCLUSION

Both seasonal and circadian rhythm disturbances are significantly associated with ADHD symptoms. Delayed sleep onset time in ADHD may explain the increase in SAD symptoms. Treating patients with SAD for possible ADHD and delayed sleep onset time may reduce symptom severity in these complex patients.

Seasonal variations in sleep disorders of nurses

AIMS AND OBJECTIVES

To investigate the difference between nurses and the general population regarding seasonal variations in sleep disorders during 2004-2008. The effects of season and group interaction on sleep disorders with regard to different comorbidities were also examined.

BACKGROUND

Studies on seasonal variations in sleep disorders were mainly conducted in Norway for the general population. Furthermore, whether different comorbidities cause seasonal variations in sleep disorders in nurses remains unknown.

DESIGN

A retrospective study.

METHODS

Data from the Taiwan National Health Insurance Research Database were used in generalised estimating equation Poisson distribution models to investigate the differences in sleep disorders between nurses and the general population diagnosed with sleep disorders (each n = 7643) as well as the interaction effects of sleep disorders between the groups with respect to different seasons. Furthermore, the interaction effects between groups and seasons on sleep disorders in the subgroups of comorbid anxiety disorders and depressive disorders were studied.

RESULTS

Both the nurses and the general population had fewer outpatient visits for sleep disorders in winter than in other seasons. The nurses had fewer outpatient visits for sleep disorders than the general population did in each season. The nurses had more outpatient visits for sleep disorders in winter than in summer compared with the general population in the comorbid depressive disorder subgroup but not in the comorbid anxiety disorder subgroup.

CONCLUSIONS

Nurses and the general population exhibited similar seasonal patterns of sleep disorders, but nurses had fewer outpatient visits for sleep disorders than the general population did in each season. For nurses with comorbid depressive disorders, outpatient visits for sleep disorders were more numerous in winter than in summer, potentially because nurses with comorbid depressive disorders are affected by shorter daylight exposure during winter.

RELEVANCE TO CLINICAL PRACTICE

Depression and daylight exposure may be considered in mitigating sleep disorders in nurses.

Relationships Between Questionnaire Ratings of Sleep Quality and Polysomnography in Healthy Adults

This study aimed to examine the association between polysomnographic sleep and subjective habitual sleep quality and restoration from sleep. Thirty-one normal sleepers completed the Karolinska Sleep Questionnaire and multiple home polysomnography recordings (n = 2-5). Using linear regression, sleep quality and restoration were separately analyzed as functions of standard polysomnography parameters: sleep efficiency, total sleep time, sleep latency, stage 1 and 2 sleep, slow-wave sleep, rapid eye movement sleep, wake time after sleep onset, and awakenings (n), averaged across recordings. Stage 2 and slow-wave sleep predicted worse and better sleep quality, respectively. Also, slow-wave sleep predicted less subjective restoration, although adjustment for age attenuated this relation. Our findings lend some physiological validity to ratings of habitual sleep quality in normal sleepers. Data were less supportive of a physiological correlate of ratings of restoration from sleep.

Sleep patterns as a predictor for length of stay in a psychiatric intensive care unit

Systematic evaluations of the relationship between sleep patterns and length of stay in psychiatric intensive care units (PICUs) are lacking. The aims of the present study were to explore if sleep duration or night-to-night variations in sleep duration the first nights predict length of stay in a PICU. Consecutive patients admitted to a PICU were included (N=135) and the nurses registered the time patients were observed sleeping. In the three first nights, the mean sleep duration was 7.5 (±3.2)h. Sleep duration the first night correlated negatively with the length of stay for patients with schizophrenia. The mean difference in sleep duration from night one to night two were 3.3 (±3.0)h and correlated with length of stay for the whole group of patients, but especially for patients with schizophrenia. Patients of all diagnostic groups admitted to a PICU had pronounced intra-individual night-to-night variations in sleep duration. Stabilizing night-to-night variations of sleep duration might be a major goal in treatment.

Using the Karolinska Sleep Questionnaire to identify obstructive sleep apnea syndrome in a sleep clinic population

INTRODUCTION

In Scandinavia, portable monitoring has virtually replaced standard polysomnography for diagnosis of obstructive sleep apnea syndrome (OSAS). Because waiting times for specialized OSAS care remain long, an accurate screening tool to exclude low-risk patients from diagnostic testing would be valuable.

OBJECTIVES

To examine the diagnostic accuracy of the Karolinska Sleep Questionnaire (KSQ) for OSAS.

METHODS

Consecutive patients, 30–66 years old, attending a large sleep clinic in Sweden for OSAS evaluation completed the KSQ and underwent in-home portable monitoring and medical history evaluation. OSAS was defined as apnea-hypopnea index ≥5 with symptoms of disease. We calculated sensitivity and specificity of apnea/snoring and sleepiness indices of the KSQ. Retrospectively, we combined six KSQ items (snoring, breathing cessations, disturbed sleep, etc.) and four clinical variables (age, sex, body mass index, smoking status) predictive of OSAS into a new instrument, which we also evaluated. Instrument score ranged between 0 and 21; a higher score indicated more severe symptoms.

RESULTS

Of 103 patients, 62 were diagnosed with OSAS. Sensitivity and specificity of the indices were 0.56 and 0.68 (apnea/snoring), and 0.37 and 0.71 (sleepiness). The new instrument performed optimally at a score of 9. Sensitivity was 0.76 (95% confidence interval 0.63–0.86) and specificity 0.88 (0.74–0.96). Between 19.4% and 50.5% of patients were unaware of having apnea/snoring symptoms.

CONCLUSIONS

Diagnostic accuracy of the apnea/snoring and sleepiness indices for OSAS was poor but could be improved by combining clinical and KSQ items. The usefulness of the apnea/snoring index and the combined instrument was questionable because of extensive symptom unawareness.

Ethnic differences in seasonal affective disorder and associated factors among five immigrant groups in Norway

BACKGROUND

Research studies on seasonal affective disorder (SAD) among immigrant populations are scarce. The objective of this article was to explore the associated risk and protective factors on prevalence of winter SAD (W-SAD), sub syndromal SAD (S-SAD) and Summer-SAD among five immigrant groups living in Oslo, Norway.

METHODS

The Oslo Immigrants Health study (innvandrer HUBRO, 2002), is a large cross sectional epidemiological survey conducted among five of the largest immigrant groups living in Oslo. 1047 subjects were included in the analysis out of 3019 who participated in the survey. Mailed questionnaire which included selected items of the seasonal pattern assessment questionnaire (SPAQ), Hopkins symptom check list (HSCL) and other variables were used in the analysis.

RESULTS

The lowest levels of W-SAD were found among Sri Lankan men and women and the highest among Iranians. W-SAD was significantly associated with country of birth, younger age, smoking, presence of mental distress, frequent visits to general practitioner or psychiatrist, self reported poor health and presence of chronic disorders. S-SAD was significantly associated with country of birth, smoking and higher levels of alcohol consumption.

LIMITATIONS

SPAQ was not culturally validated. Poor response rate (39.7%) can also be considered as a limitation.

CONCLUSIONS

Ethnic differences in W-SAD and S-SAD were observed. Sri Lankans had the lowest levels of W-SAD. However, there is a need for culturally validated instruments and further research must focus on exploring protective factors for SAD.

Associations between sleep characteristics, seasonal depressive symptoms, lifestyle, and ADHD symptoms in adults

OBJECTIVE

The authors explored associations between ADHD symptoms, seasonal depressive symptoms, lifestyle, and health.

METHOD

Adult ADHD patients (n = 202) and controls (n = 189) completed the ASESA questionnaire involving lifestyle, eating pattern, and physical and psychological health, and validated measures on ADHD and sleep. ASESA is the Dutch acronym for inattention, sleep, eating pattern, mood, and general health questionnaire.

RESULTS

Indication for delayed sleep phase syndrome (DSPS) was 26% in patients and 2% in controls (p < .001). Patients reported shorter sleep, longer sleep-onset latency, and later midsleep. Shorter (R (2) = .21) and later (R (2) = .27) sleep were associated with hyperactivity, male gender, younger age, and seasonal depressive symptoms. Seasonal depressive symptoms were related to hyperactivity, female gender, unemployment, and late sleep (pseudo R (2) = .28). Higher body mass index (BMI) was associated with shorter sleep in patients (ρ = -.16; p = .04) and controls (ρ = -.17; p = .02). Longer sleep showed lower odds for indication of metabolic syndrome (OR = -0.17; p = .053).

CONCLUSION

DSPS is more prevalent in ADHD and needs further investigation to establish treatment to prevent chronic health issues.

A reliability and validity study of the Bergen Shift Work Sleep Questionnaire in nurses working three-shift rotations

The "Bergen Shift Work Sleep Questionnaire" (BSWSQ) was developed to systematically assess discrete sleep problems related to different work shifts (day, evening, night shifts) and rest days. In this study, we assessed the psychometric properties of the BSWSQ using a sample of 760 nurses, all working in a three-shift rotation schedule: day, evening, and night shifts. BSWSQ measures insomnia symptoms using seven questions: >30-min sleep onset latency, >30-min wake after sleep onset, >30-min premature awakenings, nonrestorative sleep, being tired/sleepy at work, during free time on work days, and when not working/on vacation. Symptoms are assessed separately for each work shift and rest days, as "never," "rarely," "sometimes," "often," "always," or "not applicable." We investigated the BSWSQ model fit, reliability (test-retest of a subsample, n = 234), and convergent and discriminant validity between the BSWSQ and Epworth Sleepiness Scale, Fatigue Questionnaire, and Hospital Anxiety Depression Scale. We also investigated differences in mean scores between the different insomnia symptoms with respect to different work shifts and rest days. BSWSQ demonstrated an adequate model fit using structural equation modeling: root mean square error of approximation = .071 (90% confidence interval [CI] = .066-.076), comparative fit index = .91, and chi-square/degrees of freedom = 4.41. The BSWSQ demonstrated good reliability (test-retest coefficients p <  .001). We found good convergent and discriminant validity between BSWSQ and the other scales (all coefficients p <  .001). There were significant differences between the overall/composite scores of the various work shifts. Night shift showed the highest score compared to day and evening shifts as well as to rest days (all post hoc comparisons p <  .001). Mean scores of different symptoms also varied significantly within the individual work shifts. We conclude that the BSWSQ meets the necessary psychometric standards, enabling systematic study of discrete insomnia symptoms in different work shifts.

Seasonal variations in sleep problems at latitude 63°-65° in Norway: The Nord-Trondelag Health Study, 1995-1997

Most studies on seasonal variability in sleep have asked participants if they think their sleep quality varies with the seasons, which reveals the research hypothesis to the participants. To date, the hypothesis of seasonal variation in sleep has not been tested in a large population-based fully blinded study. The aim of the current study was to investigate monthly variations in sleep problems in a geographic region of Norway with large seasonal differences in daytime light. Using data from a general health survey, the authors had access to information on sleep in the general population, collected across the seasons over 2 years without linking sleep to seasonal variation. In all, 43,045 participants (mean age, 44.6 years) of the Nord-Trøndelag Health Study, 1995-1997 (referred to as "HUNT-2"), provided reports of insomnia symptoms and time in bed in all months except July. The mean prevalence of insomnia symptoms was 12.4%. No evidence of a seasonal variation on reports of insomnia symptoms or time in bed was found. These null findings are in marked contrast to previous seasonality studies of sleep. Previous studies reporting seasonal variations in sleep and insomnia might have been subject to publication biases and lack of blinding to the research hypothesis.

Seasonal symptoms in bipolar and primary care patients

BACKGROUND

There is evidence of seasonality in bipolar affective disorder (BAD) and the preponderance of atypical symptoms in bipolar depressive episodes is also seen in winter type Seasonal Affective Disorder. Differences in seasonal symptoms between BAD and appropriate comparison populations have been scrutinised only in small studies.

METHODS

Symptoms described on the Seasonal Pattern Assessment Questionnaire (SPAQ) were compared between 183 patients with BAD and 468 patients consulting their general practitioners. Statistical analyses were adjusted for differing age and gender distributions between the two groups.

RESULTS

Compared with the general practice patients, subjects with BAD reported greater seasonal fluctuations in mood (p=0.003). On one measure BAD subjects reported increased seasonal changes in social activity (p<0.001) and greater weight fluctuation over the year (p=0.001). The most striking differences were in sleep patterns; BAD subjects slept significantly more throughout the year, and slept for a mean of 1.8h more in winter than in summer (versus a 1.0h difference in the general practice group, p<0.001). Against 20% of the general practice group, 46% of BAD patients rated seasonal changes in well-being to be at least a moderate problem.

LIMITATIONS

The SPAQ was designed as a screening instrument for Seasonal Affective Disorder, not for studies of this nature. Some of the reported differences, notably in social activity and weight changes, may reflect secondary psychosocial effects of BAD.

CONCLUSIONS

Seasonal changes, most notably winter hypersomnia, should be identified in patients with BAD. These symptoms may respond to treatments such as light therapy that are used in recurrent winter depression.

Seasonal severity of depressive symptoms as a predictor of health service use in a community-based sample

OBJECTIVE

To determine whether severity of seasonal depressive symptoms is an independent predictor of depression-specific health service use.

METHODS

Cross-sectional telephone survey evaluating mood-related symptom changes across seasons using a structured interview based on the World Mental Health Composite International Diagnostic Interview, in a community sample representative of the province of Ontario, Canada (N = 1605). This study focuses on the 625 individuals (out of a total of 1605 interviewed) who screened positive for lifetime depressive symptoms. Severity of seasonal symptoms of depression (or "seasonality") was measured using the Seasonal Depression Severity (SDS) score (range 0-36). The primary outcome was lifetime depression-specific use of health services from a physician (family physician or psychiatrist). Lifetime psychotropic medication use, use of health services from a non-physician therapist, and psychiatric hospitalization were secondary outcomes. Other important variables that are known to predict depression-specific health service use were considered in multivariable analysis.

RESULTS

In our sample of individuals with depressive symptoms, those who had used physician health services had higher SDS scores than non-users (11.5 (SD 7.2) vs. 9.7 (SD 6.4), t(616) = 3.182, P = 0.001). In multivariable analysis, SDS score was independently associated with depression-specific health service use by a physician (OR = 1.04, 95% CI 1.01-1.07, p = 0.004). The relationship between seasonality and use of psychotropic medication use was similar (OR = 1.04, 95% CI 1.01-1.07, p = 0.007).

CONCLUSIONS

Seasonality was independently associated with depression-specific health service use for individuals with depressive symptoms. The results imply that greater seasonality may independently reflect increased severity and need for treatment of depression.

Is human seasonality implicated in the risk profile for obesity?

Although seasonality might once have been a successful energy conservation strategy for people living in temperate regions, this physiological phenomenon may now foster accumulating annual weight gain and thereby feature in the risk profile for obesity. We tested the hypothesis that seasonality relates to BMI, and that this association is mediated by a preference for carbohydrates and the tendency to binge eat. In a sample of men and women, gender significantly moderated the relationship between seasonality and BMI. In men, the relationship was positive, but these two variables did not co-vary in women. Reasons why seasonality is positively associated with BMI only in men are not immediately apparent. It is possible that other gender-specific risk factors for overeating may contribute to these findings.

Using difficulty resuming sleep to define nocturnal awakenings

OBJECTIVE

Nocturnal awakenings are one of the most prevalent sleep disturbances in the general population. Little is known, however, about the frequency of these episodes and how difficulty resuming sleep once awakened affects subjective sleep quality and quantity.

METHOD

This is a cross-sectional telephone study with a representative sample consisting of 8937 non-institutionalized individuals aged 18 or over living in Texas, New York and California. The interviews included questions on sleeping habits, health, sleep and mental disorders. Nocturnal awakenings were evaluated according to their frequency per week and per night, as well as their duration.

RESULTS

A total of 35.5% of the sample reported awakening at least three nights per week. Of this 35.5%, 43% (15.2% of the total sample) reported difficulty resuming sleep once awakened. More than 80% of subjects with insomnia symptoms (difficulty initiating or maintaining sleep or non-restorative sleep) also had nocturnal awakenings. Difficulty resuming sleep was associated with subjective shorter sleep duration, poorer sleep quality, greater daytime impairment, greater consultations for sleep disturbances and greater likelihood of receiving a sleep medication.

CONCLUSIONS

Nocturnal awakenings disrupt the sleep of about one-third of the general population. Using difficulty resuming sleep identifies individuals with significant daytime impairment who are most likely to seek medical help for their sleep disturbances. In the absence of other insomnia symptoms, nocturnal awakenings alone are unlikely to be associated with daytime impairments.