Irregular sleep is linked to poorer mental health: A pooled analysis of eight studies

OBJECTIVES

Greater sleep disturbances on average are a risk factor for impaired mental health. Recent research has shown that more intraindividual variability (i.e., inconsistency) in sleep (hereafter called "sleep intraindividual variability") may also be uniquely related to mental health, even above the influence of mean sleep patterns averaged across days. The current study examined associations between sleep intraindividual variability and symptoms of anxiety, depression, and insomnia across different facets of sleep intraindividual variability (sleep duration, efficiency, and timing) and sleep measurement types (sleep diary and actigraphy).

METHODS

We pooled eight datasets (N = 3053 participants) that assessed repeated measures of sleep diary- and/or actigraphy-determined sleep across multiple days, as well as one-time measures of mental health or sleep disorder symptoms (i.e., anxiety, depression, and insomnia). Multilevel regression analyses were conducted to examine associations between sleep intraindividual variability and mental health or sleep disorder symptoms.

RESULTS

Greater diary- and actigraphy-determined sleep duration intraindividual variability was associated with more depression symptoms (diary: b=0.02, p < .001; actigraphy: b=0.03, p = .006) and more insomnia symptoms (diary: b=0.02, p < .001; actigraphy: b=0.02, p < .001). Greater diary-determined sleep efficiency intraindividual variability was associated with fewer anxiety symptoms (b=-0.23, p = .019) and fewer insomnia symptoms (b=-0.15, p < .001). Greater diary- and actigraphy-determined sleep midpoint intraindividual variability was associated with more insomnia symptoms (diary: b=0.41, p = .044; actigraphy: b=0.66, p = .021).

CONCLUSIONS

More inconsistent sleep duration and sleep timing may be a correlate of poorer mental health. Future experimental work should examine whether stabilizing sleep patterns can improve mental health outcomes.

Nightly Sleep Predicts Next-Morning Expectations for Stress and Positive Experiences

OBJECTIVE

Abundant research has linked nightly sleep as an antecedent of daily psychosocial experiences; however, less is known about sleep's influence on daily expectations of these experiences. Therefore, this research examined the day-to-day associations of sleep quality, duration, and efficiency with next-day expectations for stress(ors) and positive experiences, as well as whether these expectations were related to end-of-day reports of physical symptoms.

METHODS

In Study 1, U.S. adults ( n = 354; ages 19 to 74) completed twice-daily diaries for 10 weekdays about sleep, expectations for encountering daily stressors and positive events, and physical symptoms. In Study 2, adults in Canada ( n = 246; ages 25 to 87) wore a sleep watch for 14 consecutive days and completed mobile surveys 5×/day about sleep, stressfulness and pleasantness expectations, and physical symptoms.

RESULTS

Multilevel models indicated that self-reported sleep quality and duration, but not efficiency, were associated with lower next-day expectations for stressors (Study 1) and stressfulness (Study 2). Self-reported sleep quality (Study 1) and all sleep indices (Study 2) predicted greater next-day expectations for positive events and pleasantness, respectively. For actigraphy-assessed sleep (Study 2), only longer-than-usual actigraphic sleep duration was associated with lower stressfulness expectations, whereas both sleep duration and efficiency were positively linked with daily pleasantness expectations. Only pleasantness expectations (Study 2)-but not daily stressfulness and event expectations (Study 1)-predicted end-of-day physical symptoms.

CONCLUSION

Findings suggest the importance of sleep on expectations of next-day stress and positive experiences, of which may have implications for daily physical health.

Daily-level associations between posttraumatic stress disorder symptoms and reactions to retrieving positive autobiographical memories

Trauma survivors with posttraumatic stress disorder (PTSD) report difficulties accessing and describing positive memories. To understand these patterns, we examined daily-level relations of PTSD symptoms with affective, cognitive (dwelling/rumination; pushing memory out of one's mind; suppression; avoidance; distraction; thinking about something else; remembering negative or positive memories/events; negative or positive thoughts; accepting or disapproving memory; reinterpreting memory), and behavioral (using alcohol/drugs; smoking cigarettes; cravings for or seeking out cigarettes/alcohol/drugs; craving, seeking out, or consuming large amounts of food; dissociation; engaging in risky behaviors; sharing memories; interference with ongoing task; arousal) reactions to retrieving positive memories. Eighty-eight trauma survivors (Mage= 39.89 years; 59.1% female) completed 7 daily measures of PTSD and reactions to retrieving positive memories. Days with more PTSD severity were associated with higher odds of same-day suppression, avoidance, distraction, thinking about something else, smoking cigarettes, craving substances, craving, seeking out, or consuming large amounts of food, dissociation, remembering negative memories/events/thoughts, engaging in risky behaviors, interference with ongoing tasks, and arousal (ORs=1.10-1.22); and greater negative affect (β = 0.27). Supplemental lagged analyses indicated some associations between previous-day reactions to positive memory retrieval and next-day PTSD severity and vice versa. Trauma survivors with PTSD symptoms report negative and avoidance-oriented reactions to retrieving positive memories.

Posttraumatic Stress Disorder Symptoms and Sleep Disturbances Among Asian Indians: A Systematic Review

Substantial comorbidity exists between posttraumatic stress disorder and sleep disturbances/disorders. Such comorbidities are understudied in minority groups, including Asian Indians residing in countries outside India. Thus, we synthesized the existing literature specific to this group of Asian Indians to determine (a) prevalence estimates of posttraumatic stress disorder (PTSD) and sleep disturbances/disorders; and (b) PTSD-sleep comorbidity estimates. For this systematic review, we searched four databases (PubMed, PsycInfo, PTSDpubs, Web of Science) using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Of 3,796 screened articles, 9 articles (10 studies) met inclusion criteria. Study sample sizes ranged from 11 to 2,112 Asian Indians; studies were conducted in Singapore or Malaysia. No reviewed study examined PTSD. All studies examined sleep disturbances/disorders among Asian Indians; prevalence estimates were: 8.3% to 70.4% for short sleep duration, 2.0% to 22.9% for long sleep duration, 25.9% to 56.3% for poor sleep quality, 3.4% to 67.5% for insomnia diagnosis or probable insomnia, 7.7% for excessive daytime sleepiness, 3.8% to 54.6% for obstructive sleep apnea (OSA) diagnosis or high OSA risk, and 5.1% to 11.1% for sleep-disordered breathing. Specific to Asian Indians residing in countries outside India, this review advances PTSD-sleep literature by (a) suggesting substantial prevalence of sleep disturbances/disorders; (b) highlighting the need for culturally relevant sleep interventions; and (c) highlighting research gaps (e.g., no PTSD-focused research).

Effects of Daily Posttraumatic Stress Disorder Symptoms on Heart Rate Variability

OBJECTIVE

Posttraumatic stress disorder (PTSD) is common, debilitating, and associated with an increased risk of health problems, including cardiovascular disease. PTSD is related to poor autonomic function indicated by reduced heart rate variability (HRV). However, very little work has tested the timescale or direction of these effects, given that most evidence comes from cross-sectional studies. Documentation of when effects occur and in what direction can shed light on mechanisms of cardiovascular disease risk and inform treatment. The present study of 169 World Trade Center responders, oversampled for PTSD, tested how daily PTSD symptoms were associated with autonomic function as reflected through HRV.

METHODS

Participants ( N = 169) completed surveys of PTSD symptoms three times a day at 5-hour intervals for 4 days while also wearing ambulatory monitors to record electrocardiograms to derive HRV (i.e., mean absolute value of successive differences between beat-to-beat intervals).

RESULTS

HRV did not predict PTSD symptoms. However, PTSD symptoms during a 5-hour interval predicted reduced HRV at the next 5-hour interval ( β = -0.09, 95% confidence interval = -0.16 to -0.02, p = .008). Results held adjusting for baseline age, current heart problems, and current PTSD diagnosis.

CONCLUSIONS

Findings underscore growing awareness that PTSD symptoms are not static. Even their short-term fluctuations may affect cardiovascular functioning, which could have more severe impacts if disruption accumulates over time. Research is needed to determine if momentary interventions can halt increases in PTSD symptoms or mitigate their impact on cardiovascular health.

Impacts of repeated retrieval of positive and neutral memories on posttrauma health: An investigative pilot study

BACKGROUND AND OBJECTIVES

Evidence indicates that positive memory processes play a role in the etiology and maintenance of posttraumatic stress symptoms (PTSS) and related posttrauma health indicators. To extend this research, the current pilot study examined if repeated retrieval of positive vs. neutral memories was associated with (1) less PTSS and depression severity; and (2) improved affect and cognitions (fewer posttrauma cognitions, more positively-valenced affect, less negatively-valenced affect, less negative affect interference, less anhedonia, retrieval of more positive specific memories, retrieval of fewer negative specific memories).

METHODS

Twenty-five trauma-exposed participants were randomly assigned to a positive or neutral memory task condition. They participated in four weekly experimental sessions facilitated by an experimenter virtually; each consecutive session was separated by 6-8 days. We conducted mixed between-within subjects ANOVAs to examine study hypotheses.

RESULTS

No interaction effects were significant. There were significant main effects of time on PTSS and depression severity, posttrauma cognitions, positively-valenced and negatively-valenced affect, and negative affect interference.

LIMITATIONS

We used self-report measures, small and non-clinical sample with limited demographic diversity, and virtual format; did not record memory narratives; and did not have a trauma memory condition.

CONCLUSIONS

Based on pilot data, our findings suggest that individuals who retrieve positive or neutral memories repeatedly may report less PTSS and depression severity, fewer posttrauma cognitions, and improved affect. Results provide an impetus to examine impacts of and mechanisms underlying memory interventions (beyond a sole focus on negatively-valenced memories) in trauma work.

Perceived psychological control relates to coping-related drinking motives via social anxiety among adolescents: A cross-sectional mediation analysis

Accumulating evidence suggests that particular parenting behaviors (e.g., elevated psychological control) may increase risk for both problematic social anxiety and alcohol use among youth; however, no work has yet examined these factors together in a single model. Building developmentally sensitive models of problematic alcohol use trajectories is key to developing effective prevention and intervention strategies. The present study includes 94 adolescents (ages 14-17 years; 53.3% girls; 89.2% White) entering a treatment facility for a variety of internalizing and externalizing forms of psychological distress. Levels of perceived parental psychological control, social anxiety, and coping-related drinking motives were assessed. Higher levels of perceived psychological control were associated with a greater endorsement of coping-related drinking motives; however, a significant proportion of that association was accounted for by elevated social anxiety symptoms. These data extend the existing literature and lay groundwork for more sophisticated experimental and longitudinal designs to corroborate the findings. Moreover, personality-targeted drinking interventions for adolescents may benefit from identifying elevated perceived psychological control as a developmentally relevant risk factor for social anxiety and problematic drinking motives and administering relevant interventions (e.g., personality-targeted coping skills training, parent-involved care) before drinking patterns are established.

Latent profiles of posttraumatic stress disorder symptoms and sleep disturbances in relation to drinking to cope motives among college students

BACKGROUND

Posttraumatic stress disorder (PTSD), sleep disturbances, and problematic alcohol use are frequently comorbid. Research shows that individuals with more PTSD symptom severity and poorer sleep are highly susceptible to drinking alcohol to cope with negative affect. The current study examined the number and nature of different subgroups of trauma-exposed college students based on endorsed PTSD symptoms and sleep disturbances; and how such subgroups relate to drinking to cope motives.

METHOD

The sample included 474 trauma-exposed college students (Mage = 20.69 years; 75.50% female) who completed self-report surveys.

RESULTS

Latent profile analyses revealed three subgroups: High PTSD-Sleep Disturbances (n = 71), Moderate PTSD-Sleep Disturbances (n = 135), and Low PTSD-Sleep Disturbances (n = 268). Results indicated that college students in the Low PTSD-Sleep Disturbances group endorsed the lowest amount of coping-related drinking motives; however, college students in the Moderate PTSD-Sleep Disturbances group did not endorse significantly different levels of coping-related drinking motives than college students in the High PTSD-Sleep Disturbances group.

CONCLUSIONS

College students with subclinical presentations of psychopathology are at risk for endorsing risky drinking motives. As they adjust to a stressful environment with a culture of heavy drinking, providing context-relevant intervention efforts such as adaptive coping strategies, relaxation skills designed to facilitate restful sleep, and trauma-informed care may be highly beneficial for college students.

The role of affect in associations between sleep disturbances and posttraumatic stress disorder symptoms: A systematic review

Strong evidence supports a bidirectional association between sleep disturbances and posttraumatic stress disorder (PTSD). Affect - temporary internal states experienced as feeling good or bad, energized or enervated - may play a central role in explaining this link. The current systematic review summarizes the literature on associations between sleep, PTSD, and affect among trauma-exposed adults. We systematically searched five electronic databases (PubMed, PsycInfo, PTSDpubs, Web of Science, CINAHL) using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Of 2656 screened articles, 6 studies met inclusion criteria. Four findings emerged: (1) greater insomnia symptom severity predicted greater PTSD symptom severity above the influence of negative affect, (2) negative affect mediated the effect of sleep quality on next-day PTSD symptom severity, (3) positive affect mediated the effect of PTSD symptom severity on insomnia symptom severity and sleep disturbances, and (4) greater negative affect (specifically, greater anger) was associated with greater severity of PTSD and sleep disturbances. Findings highlight areas for future research, such as the need to investigate more dimensions, timescales, and methods of studies simultaneously assessing affect, sleep, and PTSD, as well as the need for more longitudinal and experimental work to determine causality across these constructs.

Intraindividual variability in sleep duration and college degree attainment

The objective of the current study was to examine the relationship between sleep characteristics and college degree attainment. Participants were 968 college students (72% female; mean age 19.7 [1.7]). Participants completed a psychosocial and sleep questionnaire battery followed by one week of daily sleep diaries. Academic degree completion data was obtained from the university registrar 10 years later. Logistic regression examined whether mean and variability in sleep duration and sleep efficiency and insomnia symptoms predicted degree attainment, adjusting for age, gender, semester, grade point average (GPA), and perceived stress. The strongest predictors of degree attainment were female gender (OR = 0.67), greater age (OR = 1.32), GPA (OR = 1.97), and lower intraindividual variability in sleep duration (OR = 0.99). Results highlight the importance of examining variability in sleep duration in addition to mean sleep duration in predicting college retention. Future research should use a combination of objective and subjective measures to explore the impact of sleep factors, including variability, on degree completion and other academic metrics.

Treatment of comorbid sleep disorders and posttraumatic stress disorder in U.S. active duty military personnel: A pilot randomized clinical trial

Insomnia and nightmares are common in patients with posttraumatic stress disorder (PTSD). They are associated with worse psychological and physical health and worse PTSD treatment outcomes. In addition, they are resistant to PTSD treatments, which do not typically address sleep disorders. Cognitive behavioral therapy for insomnia and nightmares (CBT-I&N) and cognitive processing therapy (CPT) for PTSD are first-line treatments, but limited evidence exists guiding the treatment of individuals with all three disorders. The current study randomized U.S. military personnel (N = 93) to one of three conditions: CBT-I&N delivered before CPT, CBT-I&N delivered after CPT, or CPT alone; all groups received 18 sessions. Across groups, participants demonstrated significantly improved PTSD symptoms. Because the study was terminated prematurely due to challenges with recruitment and retention, it was underpowered to answer the initially intended research questions. Nonetheless, statistical findings and relevant clinically meaningful changes were observed. Compared to participants who received CPT alone, those who received CBT-I&N and CPT, regardless of sequencing, demonstrated larger improvements in PTSD symptoms, d = -0.36; insomnia, d = -0.77; sleep efficiency, d = 0.62; and nightmares, d = -.53. Compared to participants who received CBT-I&N delivered before CPT, those who received CBT-I&N delivered after CPT demonstrated larger improvements in PTSD symptoms, d = 0.48, and sleep efficiency, d = -0.44. This pilot study suggests that treating comorbid insomnia, nightmares, and PTSD symptoms results in clinically meaningful advantages in improvement for all three concerns compared to treating PTSD alone.

Daily Sleep-Stress Reactivity and Functional Impairment in World Trade Center Responders

BACKGROUND

How sleep is impacted by stress ("sleep reactivity to stress") and how stress is impacted by sleep ("stress reactivity to sleep") are trait-like characteristics of individuals that predict depression, anxiety, and insomnia. However, pathways between reactivity and functional impairment (e.g., impairment in social relationships and interpersonal functioning) have not been explored, which may be a critical pathway in understanding the link between reactivity and the development of psychological disorders.

PURPOSE

We examined associations between reactivity and changes in functional impairment among a cohort of 9/11 World Trade Center responders.

METHODS

Data from 452 responders (Mage = 55.22 years; 89.4% male) were collected between 2014 and 2016. Four baseline sleep and stress reactivity indices (i.e., sleep duration and efficiency reactivity to stress; stress reactivity to sleep duration and efficiency) were calculated from 14 days of sleep and stress data using random slopes from multilevel models. Functional impairment was assessed approximately 1 year and 2 years after baseline via semi-structured interviews. Latent change score analyses examined associations between baseline reactivity indices and changes in functional impairment.

RESULTS

Greater baseline sleep efficiency reactivity to stress was associated with decreases in functioning (β = -0.05, p = .039). In addition, greater stress reactivity to sleep duration (β = -0.08, p = .017) and sleep efficiency (β = -0.22, p < .001) was associated with lower functioning at timepoint one.

CONCLUSION

People who are more reactive to daily fluctuations in stress and sleep have poorer interpersonal relationships and social functioning. Identifying individuals with high reactivity who could benefit from preventative treatment may foster better social integration.

Do positive memory characteristics influence daily-level trajectories of posttraumatic stress disorder symptoms? an exploratory daily diary study

BACKGROUND AND OBJECTIVES

Evidence links posttraumatic stress disorder (PTSD) with positive memory characteristics. To extend this research, we utilized daily diary data to examine (1) concurrent/lagged associations between daily PTSD symptom severity and positive memory vividness/accessibility; and (2) associations between baseline-assessed positive memory characteristics and changes in PTSD symptom severity over time.

DESIGN AND METHODS

A sample of 238 trauma-exposed participants (Mage = 21.19 years; 86% women) completed baseline and 10 daily measures of PTSD symptoms and positive memory characteristics. Multilevel models covaried for gender, number of trauma types, and number of completed surveys.

RESULTS

Days with greater PTSD symptom severity than an individual's average associated with less vividness (b = -0.02, p < .001) and accessibility (b = -0.02, p < .001) of the positive memory on the same day. Days with greater positive memory vividness (b = -1.06, p < .001) and accessibility (b = -0.93, p < .001) than an individual's average associated with less PTSD symptom severity on the same day. There were no significant lagged associations between these constructs. There were significant interactions between baseline-assessed psychological distance and time (b = -0.04, p  = .042) and between baseline-assessed visual perspective and time (b = 0.05, p = .023) on PTSD symptom severity across days.

CONCLUSIONS

Findings inform positive memory intervention targets for PTSD and provide impetus for longitudinal investigations on their inter-relations.

Sleep disturbances and depression are bidirectionally associated among college student athletes across COVID-19 pandemic exposure classes

College athletes may be vulnerable to sleep disturbances and depression during the COVID-19 pandemic as a result of large shifts in social and athletic obligations. In a national sample of college athletes, we examined the associations between sleep disturbances and depression across two timepoints, using COVID-19 exposure as a moderator. Data were collected from 2098 NCAA Division I, II, and III college athletes during two timepoints, from April 10 to May 23, and from August 4 to September 15, 2020. First, a latent class analysis was conducted with five indicators of levels of COVID-19 exposure to determine different exposure profiles. Second, to examine the directionality of associations between sleep disturbance and depression, a cross-lagged panel model was added to the latent class membership structural equation model; this allowed for testing of moderation by COVID exposure class membership. Four highly homogeneous, well-separated classes of COVID-19 exposure were enumerated: Low Exposure (57%); Quarantine Only (21%); High Other, Low Self Exposure (14%); and High Exposure (8%). COVID-19 exposure class membership did not significantly moderate associations between sleep disturbances and depression. However, student athletes significantly differed in T2 depression by their COVID-19 exposure class membership. Depression and sleep disturbances were positively correlated at both timepoints (r _T1 = 0.39; r _T2 = 0.30). Additionally, cross-lagged associations were found such that T2 depression was associated with T1 sleep disturbances (β = 0.14) and vice versa (β = 0.11). These cross-lagged associations were not significantly affected by athletes' level of COVID-19 exposure during the beginning of the pandemic.

Associations between positive memory count and hazardous substance use in a trauma-exposed sample: Examining the moderating role of emotion dysregulation

OBJECTIVES

Research has demonstrated links between autobiographical memory retrieval and hazardous substance use. However, limited work has examined relations between positive autobiographical memories and hazardous substance use, as well as moderating factors influencing these relations. Thus, we examined the potential moderating roles of negative and positive emotion dysregulation in the relations between count of retrieved positive memories and hazardous substance use (alcohol and drug use separately).

METHODS

Participants were 333 trauma-exposed students (Mage  = 21.05; 85.9% women) who completed self-report measures assessing positive memory count, hazardous alcohol and drug use, negative emotion dysregulation, and positive emotion dysregulation.

RESULTS

Positive emotion dysregulation significantly moderated the association between positive memory count and hazardous alcohol use (b = 0.04, 95% confidence interval [CI] [0.01, 0.06], p = 0.019), as well as the association between positive memory count and hazardous drug use (b = 0.02, 95% CI [0.01, 0.03], p = 0.002). Individuals with more positive emotion dysregulation had stronger associations between increases in positive memory count and increased hazardous substance use.

CONCLUSION

Findings indicate that trauma-exposed individuals who retrieve more positive memories and experience difficulties regulating positive emotions report greater hazardous substance use. Positive emotion dysregulation may be an important target for memory-based interventions among trauma-exposed individuals who report hazardous substance use.

The Role of Emotion Dysregulation in the Relationship Between Sleep Disturbances and PTSD Symptom Severity

ABSTRACT

Emotion dysregulation is implicated in the development, maintenance, and treatment of sleep disturbances and posttraumatic stress disorder (PTSD) separately. However, few studies have assessed interactions among these variables. To address this gap, this study examined whether the associations of sleep quality and sleep quantity with PTSD severity were stronger at higher levels of negative and positive emotion dysregulation in a community sample of 199 trauma-exposed individuals. This study found that both poorer sleep quality and lower sleep quantity were associated with greater PTSD severity at low to average (but not high) levels of negative emotion dysregulation. Positive emotion dysregulation did not moderate the relationships between sleep quality or quantity and PTSD severity. Exploratory additive multiple moderation analyses showed significant associations between poorer sleep quality and lower sleep quantity with greater PTSD severity at low to average levels of negative emotion dysregulation, coupled with any level of positive emotion dysregulation. Findings inform theoretical perspectives on the sleep-PTSD relationship and clinical applications of targeting emotion dysregulation in the treatment of sleep disturbances and PTSD symptoms for trauma-exposed individuals.

Positive Affect Processes and Posttraumatic Stress Disorder Symptoms: Findings from an Open Label and Uncontrolled Pilot Study using the Positive Memory Processing Technique

Recently, a five-session Processing of Positive Memories Technique (PPMT) was proposed as a novel intervention for posttraumatic stress disorder (PTSD). One purported outcome of and mechanism underlying PPMT's effects on PTSD is improved positive affect processes. In this uncontrolled pilot study, we examined whether PPMT was associated with decreases in PTSD severity; and whether changes in positive affect levels, reactivity, and dysregulation related to changes in PTSD severity across sessions. The sample included 16 trauma-exposed participants seeking services at a University Psychology Clinic (Mage=27.44 years; 68.80% women). Multilevel linear growth models examined the main effects of each positive affect variable and their interactions with time on PTSD severity. PTSD severity decreased across PPMT treatment in each model (bs=-0.43 to -0.33; d=-0.03; ps<.001-0.008). There was a main effect of positive emotion dysregulation (b=1.16, d=0.11; p=0.009), but not of positive affect levels (p=0.821) or reactivity (p=0.356) on PTSD severity. However, positive affect processes did not modify the trajectory of PTSD severity across treatment. Regarding PTSD symptom clusters, there was an interaction between positive affect levels and time on alterations in arousal and reactivity (AAR) cluster severity (b=-0.01, p=0.036); individuals with positive affect levels 1 SD above the mean (b=-0.18, p<0.01) and at the mean (b=-0.10, p=0.01) had greater decreases in AAR cluster severity across treatment compared to individuals with positive affect levels 1 SD below the mean (b=-0.02, p=0.710). Findings suggest that PPMT may relate to improved PTSD symptoms; and that positive affect levels/dysregulation may be worthwhile targets for future investigations.

The role of positive affect processes in the association between posttraumatic stress disorder symptoms and sleep: A multi-study design

OBJECTIVES

Posttraumatic stress disorder (PTSD) symptoms have been linked to sleep disturbances. Limited work has explored how positive affect processes may account for this relationship. Advancing research in this area, we utilized a multi-study design to investigate the role of positive affect processes (levels of positive affect, positive emotionality, hedonic deficits, negative affect interference) in the PTSD-sleep association.

METHODS

Data from 149 trauma-exposed firefighters (M_age = 38.93 ± 9.65, 5.40 % women) were collected between September 2021 and November 2021, and data from 119 trauma-exposed community members (M_age = 29.60 ± 8.67, 68.10 % women) were collected between February 2021 and December 2021. Participants completed an online survey on PTSD symptoms, sleep disturbances, and positive affect processes.

RESULTS

Positive affect levels (b = 0.03, 95 % confidence interval [CI] [0.01, 0.06]; firefighter sample), positive emotionality (b = 0.07, CI [0.03, 0.13]; community sample), and negative affect interference (b = 0.06, CI [0.01, 0.14]; community sample) significantly accounted for the associations between PTSD symptom severity and sleep disturbances controlling for the effects of gender and age.

CONCLUSION

Findings highlight the role of positive affect processes in the link between PTSD and sleep, and support addressing positive affect processes as potential targets in clinical interventions for co-occurring PTSD-sleep problems.

Investigating sleep, stress, and mood dynamics via temporal network analysis

OBJECTIVE/BACKGROUND

Prior research has emphasized the bidirectional relationships between sleep, stress, and affective states, such as depression. Given the inherent variability and fluctuations associated with sleep, assessing how sleep and affective variables function within a dynamic system may help further uncover possible causes and consequences of sleep disturbances, as well as find candidate targets for intervention. To this end, we examined dynamic relationships between self-reported stress, depressed mood, and clinically-relevant sleep parameters via temporal network analysis.

METHODS

Participants were 401 nurses (92% female, 78% White, Mage = 39.47 years) who completed 14 days of sleep diaries incorporating self-reported stress and depression, as well as total sleep time, sleep efficiency, sleep onset latency, and wake after sleep onset.

RESULTS AND CONCLUSIONS

Overall, total sleep time emerged as a highly influential variable in the context of "outstrength centrality," meaning total sleep time had numerous outward connections with other variables (e.g., stress and sleep efficiency). The high outstrength centrality of total sleep time suggests this variable is a source of activation within this dynamic system. Conversely, stress showed high "instrength centrality," suggesting this variable was highly impacted by other variables in the system, such as depressed mood and sleep efficiency. These findings emphasize the importance of assessing unfolding sleep processes within a naturalistic setting, and implicate the role of total sleep time in fueling depressed mood and stress. Discussion emphasizes implications of these results for understanding the connections between sleep, stress, and depression as well as clinical relevance of these findings.

Longitudinal associations between PTSD and sleep disturbances among World Trade Center responders

OBJECTIVE/BACKGROUND

Post-traumatic stress disorder (PTSD) is characterized by substantial disruptions in sleep quality, continuity, and depth. Sleep problems also may exacerbate PTSD symptom severity. Understanding how PTSD and sleep may reinforce one another is critical for informing effective treatments.

PATIENTS/METHODS

In a sample of 452 World Trade Center 9/11 responders (mean age = 55.22, 89.4% male, 66.1% current or former police), we examined concurrent and cross-lagged associations between PTSD symptom severity, insomnia symptoms, nightmares, and sleep quality at 3 time points ∼1 year apart. Data were analyzed using random intercept cross-lagged panel models.

RESULTS

PTSD symptom severity and sleep variables were relatively stable across time (intraclass correlation coefficients: 0.63 to 0.84). Individuals with more insomnia symptoms, more nightmares, and poorer sleep quality had greater PTSD symptom severity, on average. Within-person results revealed that greater insomnia symptoms and nightmares at Time 1 were concurrently associated with greater PTSD symptoms at Time 1. Insomnia symptoms were also concurrently associated with PTSD symptoms at Times 2 and 3, respectively. Cross-lagged and autoregressive results revealed that PTSD symptoms and nightmares predicted nightmares at the next timepoint.

CONCLUSIONS

Overall, results suggest PTSD and sleep problems may be linked at the same point in time but may not always influence each other longitudinally. Further, individuals who experience more sleep disturbances on average may suffer from more debilitating PTSD. Evidence-based treatments for PTSD may consider incorporating treatment of underlying sleep disturbances and nightmares.

Racial/ethnic variations in inflammatory markers: exploring the role of sleep duration and sleep efficiency

Individuals from minoritized racial/ethnic groups have higher levels of circulating inflammatory markers. However, the mechanisms underlying these differences remain understudied. The objective of this study was to examine racial/ethnic variations in multiple markers of inflammation and whether impaired sleep contributes to these racial/ethnic differences. Nurses from two regional hospitals in Texas (n = 377; 71.62% White; 6.90% Black; 11.14% Hispanic, 10.34% Asian; mean age = 39.46; 91.78% female) completed seven days of sleep diaries and actigraphy to assess mean and variability in total sleep time (TST) and sleep efficiency (SE). On day 7, blood was drawn to assess 4 inflammatory markers: C-reactive protein (CRP), Interleukin-6 (IL-6), Interleukin-1 beta (IL-1β), and tumor necrosis factor-alpha (TNF-α). Results from regression models showed differences in inflammatory markers by race/ethnicity, adjusting for age and gender. The associations between sleep parameters and inflammatory markers also varied by race/ethnicity. Among White nurses, lower mean and greater variability in actigraphy-determined TST and greater variability in diary-determined TST were associated with higher levels of IL-6. Among Black nurses, lower mean diary-determined SE was associated with higher levels of IL-6 and IL-1β. Among Hispanic nurses, greater diary-determined mean TST was associated with higher CRP. Among Asian nurses, greater intraindividual variability in actigraphy-determined SE was associated with lower CRP. Among nurses, we did not find racial/ethnic disparities in levels of inflammation. However, analyses revealed differential relationships between sleep and inflammatory markers by race/ethnicity. Results highlight the importance of using a within-group approach to understand predictors of inflammatory markers.

How much does sleep vary from night-to-night? A quantitative summary of intraindividual variability in sleep by age, gender, and racial/ethnic identity across eight-pooled datasets

Habitual sleep duration and efficiency vary widely by age, gender, and racial/ethnic identity. Despite growing research on the importance of night-to-night, intraindividual variability (IIV) in sleep, few studies have examined demographic differences in sleep IIV. The present study describes typical sleep IIV overall and by demographics among healthy sleepers. Eight datasets of healthy sleepers (N = 2,404; 26,121 total days of sleep data) were synthesised to examine age, gender, and racial/ethnic identity differences in sleep IIV measured via diaries, actigraphy, and electroencephalography (EEG). Sleep IIV estimates included the intraindividual standard deviation (iSD), root mean square of successive differences (RMSSD), coefficient of variation (CV), and a validated Bayesian Variability Model (BVM). There was substantial IIV in sleep across measurement types (diary, actigraphy, EEG) for both sleep duration (iSD: 85.80 [diary], 77.41 [actigraphy], 67.04 [EEG] minutes; RMSSD: 118.91, 108.89, 91.93 minutes; CV: 19.19%, 19.11%, 18.57%; BVM: 60.60, 58.20, 48.60 minutes) and sleep efficiency (iSD: 5.18% [diary], 5.22% [actigraphy], 6.46% [EEG]; RMSSD: 7.01%, 7.08%, 8.44%; CV: 5.80%, 6.27%, 8.14%; BVM: 3.40%, 3.58%, 4.16%). Younger adults had more diary and actigraphy sleep duration IIV. Gender differences were inconsistent. White and non-Hispanic/Latinx adults had less IIV in sleep duration and efficiency compared to racial/ethnic minority groups. Even among healthy sleepers, sleep varies widely from night-to-night. Like mean sleep, there also may be disparities in IIV in sleep by demographic characteristics. Study results help characterise normative values of sleep IIV in healthy sleepers.

Shift Work Disorder Index: initial validation and psychosocial associations in a sample of nurses

STUDY OBJECTIVES

Shift work is common yet does not always result in Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5)-defined shift work sleep disorder (SWD). This study reports on the reliability and validity of the DSM-5 informed Shift Work Disorder Index (SWDI), the presence of probable SWD in nurses, and demographic, sleep, and psychosocial correlates.

METHODS

Nurses (n = 454) completed the SWDI, psychosocial, and demographic questionnaires. Of the sample, n = 400 completed 14 days of sleep diaries, actigraphy, and additional questionnaires.

RESULTS

The global SWDI demonstrated excellent internal consistency (α = .94), as well as good convergent and divergent validity in the nurse sample. Thirty-one percent of nurses were past-month shift workers, with 14% (ie, 44% of shift workers) having probable SWD based on SWDI. Nurses who worked shift work and/or met SWD criteria were more likely to be younger and unmarried and less likely to have children than day workers and reported greater evening chronotype, insomnia, nightmares, and sleep-related impairment, greater depression, anxiety, posttraumatic stress, and perceived stress symptoms, as well as later and more variable sleep midpoint (actigraphy), shorter sleep duration (actigraphy, diaries), and lower sleep efficiency (diaries).

CONCLUSIONS

The SWDI is an efficient and valid self-report assessment of DSM-5-defined SWD. Shift work and/or SWD were prevalent and associated with worse sleep and psychosocial health, particularly among nurses with probable SWD.

CITATION

Taylor DJ, Dietch JR, Wardle-Pinkston S, et al. Shift Work Disorder Index: initial validation and psychosocial associations in a sample of nurses. J Clin Sleep Med. 2022;18(10):2339-2351.

Characterizing Patterns of Nurses' Daily Sleep Health: a Latent Profile Analysis

BACKGROUND

Nursing is a demanding occupation characterized by dramatic sleep disruptions. Yet most studies on nurses' sleep treat sleep disturbances as a homogenous construct and do not use daily measures to address recall biases. Using person-centered analyses, we examined heterogeneity in nurses' daily sleep patterns in relation to psychological and physical health.

METHODS

Nurses (N = 392; 92% female, mean age = 39.54 years) completed 14 daily sleep diaries to assess sleep duration, efficiency, quality, and nightmare severity, as well as measures of psychological functioning and a blood draw to assess inflammatory markers interleukin-6 (IL-6) and C-reactive protein (CRP). Using recommended fit indices and a 3-step approach, latent profile analysis was used to identify the best-fitting class solution.

RESULTS

The best-fitting solution suggested three classes: (1) "Poor Overall Sleep" (11.2%), (2) "Nightmares Only" (8.4%), (3) "Good Overall Sleep" (80.4%). Compared to nurses in the Good Overall Sleep class, nurses in the Poor Overall Sleep or Nightmares Only classes were more likely to be shift workers and had greater stress, PTSD symptoms, depression, anxiety, and insomnia severity. In multivariate models, every one-unit increase in insomnia severity and IL-6 was associated with a 33% and a 21% increase in the odds of being in the Poor Overall Sleep compared to the Good Overall Sleep class, respectively.

CONCLUSION

Nurses with more severe and diverse sleep disturbances experience worse health and may be in greatest need of sleep-related and other clinical interventions.

Heterogeneity in patterns of posttraumatic stress disorder symptoms and sleep disturbances among firefighters: Latent profile analyses

Firefighters are at increased risk for posttraumatic stress disorder (PTSD) symptoms and sleep disturbances due to occupational trauma exposure as well as the nature of their job (e.g., shift work, workplace stress). PTSD symptoms co-occur with sleep disturbances, including poor sleep quality, short sleep duration, and low sleep efficiency. No published studies have examined subgroups of firefighters based on PTSD symptoms and sleep disturbances. Thus, we used latent profile analysis to identify the best-fitting class solution to categorize firefighters based on endorsed PTSD symptoms and sleep disturbances and examined relations between the optimal class solution and health covariates (i.e., anger reactions, depression symptoms, emotion regulation difficulties, number of traumatic event types). The sample included 815 trauma-exposed firefighters (M_age = 38.63; 93.20% male). Results indicated three latent subgroups: High PTSD-Sleep Disturbances, Moderate PTSD-Sleep Disturbances, and Low PTSD-Sleep Disturbances. Multinomial logistic regression indicated that endorsing greater anger reactions, depression symptoms, and emotion regulation difficulties increased the chances of being in the more severe classes. Endorsing greater number of traumatic event types increased the chances of being in the Moderate vs. Low PTSD-Sleep Disturbances Classes. Findings improve our understanding of subgroups of firefighters based on PTSD and sleep disturbances and underscore the importance of addressing depression symptoms, anger management, and emotion regulation skills for firefighters reporting more severe PTSD symptoms and sleep disturbances.

COVID‐19 related distress and sleep health among trauma‐exposed South Asians: Does generational status matter?

The COVID-19 pandemic has resulted in substantial changes in individual and socio-economic factors that may negatively impact sleep health. We examined associations between COVID-19 related distress and sleep among trauma-exposed South Asian adults in the United States. Since a health advantage among foreign-born individuals has been previously noted in the literature (the 'immigrant paradox'), we also explored if generational status (number of generations one's family has been in the U.S.) moderated associations between COVID-19 related distress and sleep health. Participants were 196 trauma-exposed South Asian adults residing in the U.S. (54% male, 63% U.S.-born citizens, average age = 34.51 years), who completed measures of generational status, COVID-19 related distress, trauma exposure, sleep-related impairment (SRI), and sleep disturbances. Greater COVID-19 distress was associated with more sleep disturbances (b = 0.15, p < 0.001) and SRI (b = 0.24, p < 0.001). Generational status was not associated with sleep, nor did it modify associations between COVID-19 distress and sleep. Findings highlight the potential importance of developing interventions to reduce stress and sleep difficulties during the pandemic. Our results did not support the immigration paradox. Future studies are needed to better understand the role of generational status on sleep health across immigrant subgroups.

Daily stress and sleep associations vary by work schedule: A between- and within-person analysis in nurses

Nurses experience poor sleep and high stress due to demanding work environments. Night shift work is common among nurses and may exacerbate stress-sleep associations. We examined bidirectional associations between daily stress and sleep, and moderation by recent shift worker status and daily work schedule among nurses. Participants were 392 nurses (92% female; 78% White, mean age = 39.54, SD = 11.15) who completed 14 days of electronic sleep diaries and actigraphy. They simultaneously completed assessments of daily stress and work schedule upon awakening (day shift vs. night shift [work between 9 p.m.-6 a.m.] vs. off work). Participants were classified as recent night shift workers if they worked at least one night shift during the past 14 days (n = 101; 26%). In the entire sample, greater daily stress predicted shorter self-reported total sleep time and lower self-reported sleep efficiency that night. Shorter self-reported and actigraphy total sleep time and lower self-reported sleep efficiency predicted higher next-day stress. Compared with recent night shift workers, day workers reported higher stress after nights with shorter total sleep time. Stress-sleep associations mostly did not vary by nurses' daily work schedule. Sleep disturbances and stress may unfold in a toxic cycle and are prime targets for tailored interventions among nurses. Night shift workers may be less susceptible to the effects of short sleep on next-day stress. Research is needed to understand the short- and long-term effects of shift work and address the unique sleep challenges nurses face.

Examination of daily-level associations between posttraumatic stress disorder symptoms and COVID-19 worries

OBJECTIVE

Stressors and worries related to the COVID-19 pandemic have contributed to the onset and exacerbation of psychological symptoms such as posttraumatic stress disorder (PTSD). Using a microlongitudinal framework, we uniquely investigated bidirectional associations between daily-level PTSD symptoms and COVID-19 worries.

METHOD

Data from 42 trauma-exposed university students (M_age = 22.67 ± 5.02, 86.7% female) were collected between March and August 2020. Participants completed daily surveys for 10 days to assess PTSD symptom severity and COVID-19 worries. Multilevel regression was conducted to examine both lagged and simultaneous models of daily person-centered mean PTSD symptom severity predicting COVID-19 worries, and vice-versa.

RESULTS

Days with greater COVID-19 worries were associated with greater same-day (b = .53, SE = .19, p = .006) and next-day (b = .65, SE = .21, p = .003) PTSD symptom severity. Additionally, days with greater PTSD symptom severity were associated with greater same-day COVID-19 worries (b = .06, SE = .02, p = .006).

CONCLUSIONS

COVID-19 worries may influence same-day and next-day PTSD symptoms, and PTSD symptoms may influence same day COVID-19 worries. Findings substantiate the interplay between ongoing stress related to the COVID-19 pandemic and posttrauma symptoms and support therapeutically targeting COVID-19 stress in PTSD treatments to potentially impact posttrauma symptoms. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

What goes around comes around: Nightmares and daily stress are bidirectionally associated in nurses

Nurses may experience frequent nightmares due to stressful work environments. Nightmares may also exacerbate stress among nurses, although this has yet to be tested empirically. We examined daily bidirectional associations between stress severity and nightmares, and moderation by post-traumatic stress disorder (PTSD) symptoms. 392 nurses (92% female; 78% White) completed 14 days of sleep diaries to assess previous-day stress severity and nightmare occurrence and severity. PTSD symptoms were assessed at baseline. Multilevel models were used to examine bidirectional, within-person associations between daily stress and nightmares, and cross-level moderation by baseline PTSD symptoms. 47.2% of nurses reported at least one nightmare across the two weeks. Days with greater stress were associated with higher odds of experiencing a nightmare (OR = 1.22, p = 0.001), as well as greater nightmare severity (b = 0.09, p = 0.033). Nightmare occurrence was associated with greater next-day stress severity (b = 0.15, p < 0.001). Daily stress and nightmare associations were similar for those with and without PTSD symptoms. Nightmares and stress may occur in a bidirectional fashion. Nurses face intense occupational demands and frequent exposure to potentially traumatic events. Studies should explore whether targeting nightmares and stress may improve nurses' health and well-being.

Associations Between Intraindividual Variability in Sleep and Daily Positive Affect

Recent research highlights a variety of negative outcomes associated with intraindividual variability in positive affect (PA) and in sleep. Thus, this study examined the associations of variability in multiple dimensions of sleep (quality, duration, wake after sleep onset, bedtime, rise-time) with mean and variability in PA. For 7 days, morning and evening surveys were collected online from two separate samples: community-based adults (N = 911) and university students (N = 322). Regression analyses revealed that across both samples, people with more variable sleep quality exhibited greater fluctuations in PA throughout the week and, surprisingly, higher levels of PA on average. In the community sample only, individuals with more variable sleep duration had lower and more variable PA. Findings suggest that fluctuations in sleep quality and duration are linked with daily PA outcomes, which is important to consider as technological advances and modern demands make inadequate and irregular sleep increasingly common.

Supplementary Information

The online version contains supplementary material available at 10.1007/s42761-021-00082-6.

What moderates salivary markers of inflammation reactivity to stress? A descriptive report and meta-regression

As the assessment of salivary markers of inflammation gains popularity in stress research, understanding factors that influence these markers' reactivity to stress is important. A recent meta-analysis synthesized literature on changes in salivary markers of inflammation in response to acute stressors in adults. As a supplement to this, we present pre-registered moderator analyses of salivary markers of inflammation responses to acute stress. Analyses included data from 27 studies (35 unique study samples). Outcomes were Cohen's d effect sizes for salivary biomarkers interleukin-1 beta (IL-1β), IL-6, IL-10, and tumor necrosis factor-alpha (TNF-α), from pre- to post-stress. Moderators included: college education levels of the study sample; percent of the study sample that identified as African-American; body mass index (BMI); use of a resting baseline saliva sample; and use of a social evaluative stressor. Descriptive results on saliva sample timing were also examined. Biomarkers peaked 0-60 minutes after the end of the stressor. Before removing influential outliers, no moderators of salivary inflammation reactivity emerged, though not all moderators could be tested due to missing data. After removing one influential outlier study, higher study sample average BMI was associated with greater salivary IL-1β reactivity to stress (b = 0.41, p=.007). For every 1-unit increase in study sample average BMI, effect sizes for IL-1β increased by 0.41 units. These findings suggest BMI may be important to examine when assessing salivary markers of inflammation in response to stress. As this field expands, it is important to replicate these results and consider the role of other moderators of salivary markers of inflammation reactivity to stress.

Day-to-day associations between nightly sleep and next-day well-being amid the COVID-19 pandemic in North America

OBJECTIVE

Sleep may be especially important for maintaining health and well-being in daily life amid the stress of the coronavirus disease 2019 (COVID-19) pandemic. This preregistered study examined the associations of sleep quality, duration, and efficiency with next-day physical symptoms, affect, and stressors during the COVID-19 pandemic in North America, in addition to evaluating individual differences in COVID-19 threat as a moderator.

METHOD

From mid-March to early August 2020, 1025 adults from Canada and the United States aged 18-91 reported COVID-19 threat at baseline and subsequently completed twice-daily diaries for one week about their sleep, negative affect, stressors, and physical symptoms.

RESULTS

Within-persons, nights with better-than-usual sleep quality predicted lower next-day negative affect, physical symptoms, and stressor occurrence. Better-than-usual sleep efficiency and longer-than-usual sleep duration also predicted lower next-day physical symptoms. COVID-19 threat ratings moderated several of these associations, such that individuals with higher COVID-19 threat showed weaker within-person associations of sleep duration and efficiency with next-day well-being, compared to individuals with lower-to-moderate levels of COVID-19 threat. For the reversed direction of association, stressor occurrence predicted shorter-than-usual sleep that night, but no other links between daily well-being and subsequent sleep were observed.

DISCUSSION

Sleep quality, efficiency, and duration were important predictors of daily health and well-being during the COVID-19 pandemic, but the protective associations between sleep and next-day well-being were attenuated among people with higher COVID-19 threat. These findings highlight the role of heightened stress contexts when considering the benefits of sleep on daily health and well-being.

Moderating effects of sleep difficulties on relations between posttraumatic stress disorder symptoms and positive memory count

OBJECTIVES

Posttraumatic stress disorder (PTSD) severity relates to positive memory retrieval difficulties. One variable potentially influencing this relation is sleep difficulties. We examined moderating effects of sleep difficulties (duration and quality) on relations between PTSD severity and count of specific positive memories covarying for age, gender, and depression.

METHODS

Participants were an Amazon Mechanical Turk-recruited trauma-exposed community sample of 205 respondents (M age  = 35.44; 61.40% women).

RESULTS

Moderated regression analyses indicated significant interaction effects between sleep quality (b = 0.03; p = 0.036) and PTSD severity on specific positive memory count. Among individuals reporting better sleep quality, there were negative associations between PTSD severity and specific positive memory count (b = -0.04, SE = 0.02, p = 0.010). Similar results were obtained for PTSD's intrusion and arousal clusters.

CONCLUSION

Results support targeting sleep quality and PTSD severity to improve positive memory retrieval in PTSD and memory interventions, and the importance of considering sleep when examining links between PTSD and positive memory retrieval.

Age-dependent associations among insomnia, depression, and inflammation in nurses

OBJECTIVE

Insomnia and depression have been inconsistently associated with inflammation. Age may be one important moderator of these associations. This study examined associations between insomnia and depression with inflammatory biomarkers in nurses and how these associations varied by age. Design: Participants were 392 nurses ages 18-65 (Mage = 39.54 years ± 11.15, 92% female) recruited from two hospitals. Main outcome measures: Participants completed surveys to assess insomnia and depression symptoms. Serum samples were obtained and analysed for inflammatory biomarkers interleukin-6 (IL-6), C-reactive protein (CRP), interleukin-1 beta (IL-1β), and tumour necrosis factor alpha (TNF-α). Results: Neither insomnia nor depression symptoms were associated with inflammatory biomarkers. Older age was associated with higher IL-1β, and age moderated the effects of depression symptoms on CRP and TNF-α: Greater depression symptoms were associated with higher CRP (b = .14, p = .017) and TNF-α (b = .008, p = .165) among older nurses only. Conclusion: Results suggest older nurses with higher depression symptoms may be at increased risk for elevated inflammation. Interventions should consider the role of age-related processes in modifying health and well-being. Given relatively low levels of depression in the current sample, future studies should replicate results in clinical and non-nurse samples.

The Nightmare Disorder Index: development and initial validation in a sample of nurses

STUDY OBJECTIVES

Nurses are a group at high risk for nightmares, yet little is known about the rate of nightmare disorder and associated psychosocial factors in this group in part attributable to the lack of a self-report questionnaire to assess DSM-5 criteria for nightmare disorder. Aims of the current study were to (1) report on development and initial validity of a self-report measure of DSM-5 nightmare disorder, and (2) examine the rate and associated factors of nightmare disorder among nurses.

METHODS

Nurses (N = 460) completed baseline measures online including Nightmare Disorder Index (NDI), psychosocial and demographic questionnaires. A subset (n = 400) completed 14 days of sleep diaries and actigraphy.

RESULTS

NDI demonstrated satisfactory psychometric characteristics as indicated by good internal consistency (α = 0.80), medium inter-item correlations (r = 0.50), medium to large item-total (r = 0.55-0.85) and convergent correlations (0.32-0.45), and small to medium discriminant correlations (-0.12-0.33). Per NDI, 48.7% of nurses reported no nightmares in the past month, 43.9% met partial/subthreshold criteria and 7.4% met full criteria for probable nightmare disorder. Nurses with nightmare disorder demonstrated significantly poorer psychosocial functioning (i.e. posttraumatic stress, depression, anxiety, stress) than those with subthreshold nightmare symptoms, who had poorer functioning than those with no nightmares.

CONCLUSIONS

NDI is an efficient and valid self-report assessment of nightmare disorder. Nurses have high rates of nightmares and nightmare disorder which are associated with poorer psychosocial functioning. We recommend increased nightmare screening particularly for high-risk populations such as healthcare workers.

Bi-directional relations between stress and self-reported and actigraphy-assessed sleep: a daily intensive longitudinal study

STUDY OBJECTIVES

Stress is associated with poor and short sleep, but the temporal order of these variables remains unclear. This study examined the temporal and bi-directional associations between stress and sleep and explored the moderating role of baseline sleep complaints, using daily, intensive longitudinal designs.

METHODS

Participants were 326 young adults (Mage = 23.24 ± 5.46), providing >2,500 nights of sleep altogether. Prospective total sleep time (TST), sleep onset latency (SOL), wake after sleep onset (WASO), and sleep efficiency (SE) were measured using actigraphy and sleep diaries. Perceived stress was reported three times daily between: 11:00-15:00, 15:30-19:30, and 20:00-02:00. Sleep complaints were measured at baseline using the PROMIS sleep disturbance scale. Within- and between-person sleep and stress variables were tested using cross-lagged multilevel models.

RESULTS

Controlling for covariates and lagged outcomes, within-person effects showed that higher evening stress predicted shorter actigraphic and self-reported TST (both p < .01). Conversely, shorter actigraphic and self-reported TST predicted higher next-day stress (both p < .001). Longer self-reported SOL and WASO (both p < .001), as well as lower actigraphic (p < .01) and self-reported SE (p < .001), predicted higher next-day stress. Between-person effects emerged only for self-reported TST predicting stress (p < .01). No significant results were found for the moderating role of baseline sleep complaints.

CONCLUSIONS

Results demonstrated bi-directional relations between stress and sleep quantity, and a consistent direction of worse sleep quantity and continuity predicting higher next-day stress. Results highlighted within-individual daily variation as being more important than between-individual differences when examining sleep and daytime functioning associations.

Measuring salivary markers of inflammation in health research: A review of methodological considerations and best practices

There is an increasing interest in using saliva to measure inflammatory biomarkers. Compared to blood, saliva is non-invasive, requires a lower biosafety classification, and requires less specialized personnel to collect. As the assessment of inflammation in saliva becomes more popular in psychoneuroimmunology research, the development of gold-standard methodological practices is paramount. This paper reviews different considerations for designing studies to assess salivary measures of inflammation. We review saliva collection procedures, sample storage and processing considerations, assay techniques, flow rate, correspondence with blood-based markers, and potential demographic and health moderators of levels of salivary markers of inflammation. Together, this review highlights critical gaps for future research, including calls for standardization of study protocols, transparent reporting of results, assessing predictive validity of markers of salivary inflammation for disease, and the need for assessment of participants' oral and general health status. Although additional work is needed to elucidate gold standards for study design, measurement, and analysis, salivary markers of inflammation may be a useful tool for understanding oral and peripheral inflammation dynamics non-invasively.

Associations between daily affect and sleep vary by sleep assessment type: What can ambulatory EEG add to the picture?

OBJECTIVE/BACKGROUND

Disrupted sleep can be a cause and a consequence of affective experiences. However, daily longitudinal studies show sleep assessed via sleep diaries is more consistently associated with positive and negative affect than sleep assessed via actigraphy. The objective of the study was to test whether sleep parameters derived from ambulatory electroencephalography (EEG) in a naturalistic setting were associated with day-to-day changes in affect.

PARTICIPANTS/METHOD

Eighty adults (mean age = 32.65 years, 63% female) completed 7 days of affect and sleep assessments. We examined bidirectional associations between morning positive affect and negative affect with sleep assessed via diary, actigraphy, and ambulatory EEG.

RESULTS

Mornings with lower positive affect than average were associated with higher diary- and actigraphy-determined sleep efficiency that night. Mornings with higher negative affect than average were associated with longer actigraphy-determined total sleep time that night. Nights with longer diary-determined total sleep time, greater sleep efficiency, and shorter sleep onset latency than average were associated with higher next-morning positive affect, and nights with lower diary-determined wake-after-sleep-onset were associated with lower next-morning negative affect. EEG-determined sleep and affect results were generally null in both directions: only higher morning negative affect was associated with longer rapid eye movement (REM) sleep that night.

CONCLUSIONS

Self-reported sleep and affect may occur in a bidirectional fashion for some sleep parameters. EEG-determined sleep and affect associations were inconsistent but may still be important to assess in future studies to holistically capture sleep. Single-channel EEG represents a novel, ecologically valid tool that may provide information beyond diaries and actigraphy.

Intraindividual Variability in Sleep and Levels of Systemic Inflammation in Nurses

OBJECTIVE

Disturbed sleep is common among nurses and is associated with morbidity and mortality. Inflammation may be one mechanism linking sleep and disease. However, most studies rely on retrospective questionnaires to assess sleep, which fail to account for night-to-night fluctuations in sleep across time (i.e., intraindividual variability [IIV]). We examined prospective associations between mean and IIV in sleep with inflammation markers in nurses.

METHODS

Participants were 392 nurses (mean age = 39.54 years, 92% female, 23% night-shift working) who completed 7 days of sleep diaries and actigraphy to assess mean and IIV in total sleep time and sleep efficiency. Blood was drawn on day 7 to assess inflammation markers C-reactive protein, interleukin (IL)-6, tumor necrosis factor α, and IL-1β.

RESULTS

Greater IIV in total sleep time-measured via both actigraphy and sleep diary-was associated with higher IL-6 (actigraphy: b = 0.05, p = .046, sr = 0.01; diary: b = 0.04, p = .030, sr = 0.01) and IL-1β (actigraphy: b = 0.12, p = .008, sr = 0.02; diary: b = 0.09, p = .025, sr = 0.01), but not C-reactive protein or tumor necrosis factor α. IIV in actigraphy- and sleep diary-determined sleep efficiency was not associated with inflammation biomarkers, nor were any mean sleep variables. Shift work did not moderate any associations.

CONCLUSIONS

Nurses with more variable sleep durations had elevated levels of inflammation, which may increase risk for development of inflammatory-related diseases. Research should investigate how sleep regularization may change levels of inflammation and improve health.

The Cycle of Daily Stress and Sleep: Sleep Measurement Matters

BACKGROUND

Disturbed sleep can be a cause and a consequence of elevated stress. Yet intensive longitudinal studies have revealed that sleep assessed via diaries and actigraphy is inconsistently associated with daily stress.

PURPOSE

We expanded this research by examining daily associations between sleep and stress using a threefold approach to assess sleep: sleep diaries, actigraphy, and ambulatory single-channel electroencephalography (EEG).

METHODS

Participants were 80 adults (mean age = 32.65 years, 63% female) who completed 7 days of stressor and sleep assessments. Multilevel models were used to examine bidirectional associations between occurrence and severity of daily stress with diary-, actigraphy-, and EEG-determined sleep parameters (e.g., total sleep time [TST], sleep efficiency, and sleep onset latency, and wake after sleep onset [WASO]).

RESULTS

Participants reported at least one stressor 37% of days. Days with a stressor were associated with a 14.4-min reduction in actigraphy-determined TST (β = -0.24, p = 0.030), but not with other actigraphy, diary, or EEG sleep measures. Nights with greater sleep diary-determined WASO were associated with greater next-day stressor severity (β = 0.01, p = 0.026); no other diary, actigraphy, or EEG sleep measures were associated with next-day stressor occurrence or severity.

CONCLUSIONS

Daily stress and sleep disturbances occurred in a bidirectional fashion, though specific results varied by sleep measurement technique and sleep parameter. Together, our results highlight that the type of sleep measurement matters for examining associations with daily stress. We urge future researchers to treat sleep diaries, actigraphy, and EEG as complementary-not redundant-sleep measurement approaches.

The effect of acute stress on salivary markers of inflammation: A systematic review and meta-analysis

BACKGROUND

Salivary biomarkers of inflammation are increasingly used in stress research. This systematic review and meta-analysis provides a quantitative summary of changes in salivary inflammatory markers in response to acute stress.

METHOD

The review included 1558 participants (42 unique samples, 33 studies) obtained through electronic databases (PubMed, PsycINFO, Embase), reference treeing, and articles identified by a 2015 review on a similar topic. To be eligible, articles had to be quantitative and assess change in at least one biomarker of salivary inflammation in response to acute stress in adults. The primary outcome was magnitude of change in inflammatory biomarkers (Cohen's d for repeated measures [d_av]).

RESULTS

Measures of salivary inflammation included: C-reactive protein (CRP), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, IL-13, IL-17A, IL-18, IL-21, interferon (IFN)-α, IFN-γ, and tumor necrosis factor (TNF)-α. Cytokines IL-6 (k = 26, d_av = 0.27), IL-10 (k = 11, d_av = 0.34), TNF-α (k = 10, d_av = 0.57), and IFN-γ (k = 6, d_av = 0.28) significantly increased in response to stress. Post hoc sensitivity analyses revealed that IL-1β (k = 19, d_av = 0.16) and IL-8 (k = 7, d_av = 0.30) also increased from pre- to post-stress, but findings with IFN-γ did not hold after removing one outlier study. Examination of moderators suggested that study methodology and sample demographics moderated some associations.

CONCLUSIONS

This meta-analysis revealed that certain salivary inflammatory cytokines increase in response to acute stress. Significant heterogeneity in results and moderator analyses suggest need for standardization of research protocols. Directions for future research are discussed.

Positive and Negative Affect and Salivary Markers of Inflammation Among Young Adults

BACKGROUND

Emerging evidence suggests that higher circulating levels of inflammatory biomarkers in blood are associated with higher negative affect (NA) and lower positive affect (PA). To our knowledge, the unique associations between NA and PA in daily life and salivary biomarkers of inflammation have not been examined. This study examined these associations in young adults.

METHODS

Measures of NA and PA were created from aggregated daily measures of affect (morning and evening ratings averaged across 14 days). We investigated associations between these measures and salivary C-reactive protein (CRP) and interleukin (IL)-6 in a sample of 108 young adults (60% female, mean age = 20.45 ± 1.47), a subset of whom had self-reported chronic back pain (n = 49). CRP and IL-6 were determined from saliva obtained at the end of the daily diary period.

RESULTS

After covarying for age, gender, body mass index, chronic pain status, salivary flow rate, and NA, higher PA was associated with lower salivary CRP (β = - 0.02, 95% CI (- 0.03, - 0.00) sr2 = .06, p = .01) but not IL-6; removing NA from this model did not change results. In a model with the same covariates (and PA), NA was not significantly related to CRP or IL-6. Chronic back pain status and gender did not moderate results.

CONCLUSIONS

Findings suggest that higher PA may be associated with lower salivary CRP in young adults, even after accounting for NA and demographic characteristics. Findings highlight the utility of assessing emotional states in relation to salivary markers of inflammation in future biobehavioral research.

0384 Do Nurses with High Blood Pressure Have More Sleep Disturbances Than Their Peers?

Introduction

Nurses work in stressful environments and often have rotating work schedules, which may put them at risk for disturbed sleep and health. Poor quality and short sleep duration are strong risk factors for high blood pressure (HBP). Yet few studies have examined these associations in nurses, who may be a particularly at-risk sample. To address this gap, we examined group differences in self-reported and actigraphy-assessed sleep among nurses with and without self-reported HBP.

Methods

Participants were 392 nurses (91.8% female; 77.8% white, mean age = 39.54) recruited for a parent study. Participants completed baseline questionnaires including the Pittsburgh Sleep Quality Index (PSQI), followed by 14 days of actigraphy and sleep diaries to prospectively assess 14-day mean total sleep time (TST) and sleep efficiency (SE). An independent samples t-tests was used to assess group differences in sleep variables by HBP status. Linear regression was used to further examine the association between HBP status on sleep variables when controlling for age, race, gender, ethnicity, and body mass index (BMI).

Results

Twenty-nine (7%) nurses endorsed having clinically-diagnosed HBP. Nurses with HBP had higher global PSQI scores (indicating worse sleep quality; t=2.71, p=0.007), compared to nurses who did not report HBP, with a mean difference of 1.24. When adjusting for covariates, the association between HBP and the PSQI became marginally significant (p=0.054). There were no group differences in sleep diary or actigraphy TST or SE by HBP status, nor did HBP predict these sleep variables when controlling for covariates.

Conclusion

We found that nurses who reported having clinically diagnosed HBP had poorer global sleep quality. Although limited by self-reported history of HBP diagnosis, and low endorsement of HBP in our sample, our results corroborate other findings which suggest there is a strong association between high blood pressure and disturbed sleep. Future studies should examine these associations in larger samples, assess blood pressure directly, and experimentally examine the effects of HBP treatment on sleep quality.

Support

NIH/NIAID R01AI128359-01

0225 Do Associations Between Daily Stress and Sleep Vary by Work Shift? A Within-Person Analysis in Nurses

Introduction

Longitudinal studies have shown daily stress and sleep are bidirectionally associated. Nurses are particularly likely to experience sleep disturbances and high stress due to demanding work environments. Night shift work may be a unique stressor for nurses that exacerbates associations between stress and sleep. Using a within-person design, we examined the daily bidirectional associations between stress and sleep and moderation by nightly work shift (day/off shift vs. night shift) in a large sample of nurses.

Methods

Participants were 393 nurses (91% female; 77% white, mean age = 38.4 years) recruited from two hospitals. Participants completed 14 days of sleep diaries and actigraphy to assess total sleep time (TST) and sleep efficiency (SE). They simultaneously completed assessments of stress on the previous day (0 = “not at all” to 4 = “extremely”) and daily work schedule (day/off shift vs. night shift [work between 9pm-6am]).

Results

Results indicated greater daily stress was associated with shorter diary TST (b = -9.49, p&lt;.0001) and actigraphy TST (b = -4.48, p&lt;.01), as well as lower diary SE (b = -0.56, p&lt;.001). When examining reverse pathways of sleep predicting next day stress, both diary TST (b = -0.0004, p&lt;.0001) and actigraphy TST (b = -0.0002, p = .03) predicted higher next-day stress. Lower diary SE predicted higher next-day stress (b = -0.005, p&lt;.001). Only the association between daily stress and nightly diary SE was moderated by daily work shift: only when nurses worked a day or off shift did they have a negative association between daily stress and diary SE (b = -0.68, p&lt;.0001).

Conclusion

Daily stress and sleep disturbances occurred in a bidirectional fashion for night- and day-shift working nurses. Most associations were similar regardless of daily type of work shift. Objective and subjective short TST and low subjective SE may contribute to a cycle of increased stress and are prime targets for a tailored sleep intervention in nurses. More research is needed to develop interventions to address the unique sleep health challenges faced by nurses.

Support

NIAID R01AI128359-01

0178 The Cycle of Daily Stress and Sleep: Sleep Measurement Matters

Introduction

Disturbed sleep can be both a cause and a consequence of increased stress. Yet intensive longitudinal studies have demonstrated that sleep assessed via sleep diaries and actigraphy is inconsistently associated with daily stress. We expanded this research by examining daily associations between sleep and stress using a three-fold approach to assess sleep: sleep diaries, actigraphy, and ambulatory single-channel electroencephalography [EEG].

Methods

Participants were 80 adults (M age = 32.65 years, 63% female) who completed 7 days of sleep and perceived stress assessments in a naturalistic setting (resulting in 560 possible measurement occasions). Multilevel models were used to examine bidirectional associations between daily stressor occurrence (0 = stressor did not occur, 1 = stressor occurred) and stressor severity (0 = not at all severe to 3 = very severe) and sleep parameters assessed via diary, actigraphy, and EEG (e.g. total sleep time [TST], sleep efficiency [SE], and sleep onset latency [SOL], wake after sleep onset [WASO]).

Results

Participants reported at least one stressor on 37% of days. Compared to days without a stressor experienced, days with a stressor were associated with a 14.4-minute reduction in actigraphy-determined TST the subsequent night (β = -0.24, p = 0.030). Nights with greater sleep-diary determined WASO were associated with greater next-day stressor severity (β = 0.01, p = .026). No EEG-determined sleep parameters were associated with next-day stressor occurrence or severity, or vice versa.

Conclusion

Daily stress and sleep disturbances occurred in a bidirectional fashion, though specific results varied by sleep measurement technique and sleep parameter. Together, our results highlight that type of sleep measurement matters for examining associations with daily stress. We urge future researchers to treat sleep diaries, actigraphy, and EEG as complementary — not redundant — sleep measurement approaches.

Support

Funding for this study included NIH/NIAID R01AI128359-01; DoD-VA 1I01CU000144-01; the Foundation for Rehabilitation Psychology; and General Sleep Corporation.

1063 Depression Moderates the Association Between Posttraumatic Stress Disorder and Nightmare Severity in Nurses

Introduction

Nurses report a higher prevalence of posttraumatic stress disorder (PTSD) than the general population, and approximately 18% of nurses report having depression. Nightmares are a common symptom of PTSD, and both nightmares and PTSD are correlated with depression. Nightmares may represent a possible clinical target for improving outcomes in both disorders. This study assessed associations between PTSD and depressive symptoms with nightmare severity, and whether depressive symptoms moderated associations between PTSD and nightmare severity.

Methods

Participants were 461 nurses (91% female; 77% white, mean age = 38.39 years) recruited from two hospitals for a parent study. Participants completed the Patient Health Questionnaire (PHQ-9), Post-traumatic Stress Disorder Checklist (PCL-5), and 14 days of sleep diaries to assess daily nightmare frequency and severity (on a scale of 0 = not at all severe to 3 = very severe).

Results

22.1% of participants reported at least one nightmare across the 14 days, with a mean daily nightmare frequency of 1.17 (SD = 2.15) and a mean severity of 0.11 (SD = 0.18). PCL-5 and PHQ-9 scores were significantly correlated with nightmare severity (r = 0.27; r = 0.24, respectively) and each other (r = 0.69). PHQ-9 scores moderated the association between PCL-5 scores and nightmare severity (β = -.01, SE = &lt;0.01, p = 0.015). For individuals 1 SD below the PHQ-9 mean, higher PCL-5 scores were associated with higher nightmare severity. For individuals 1 SD above the PHQ-9 mean, higher PCL-5 scores were associated with higher nightmare severity, but to a lesser degree.

Conclusion

Both depressive and PTSD symptoms were associated with more severe nightmares. Surprisingly, the association between PTSD symptoms and nightmare severity was stronger for those with lower depressive symptoms. Results suggest depression, PTSD, and nightmares may represent a partially overlapping symptom cluster. Research should investigate how nightmare treatment may reduce PTSD and depressive symptoms.

Support

NIAID R01AI128359-01

Intraindividual variability in sleep and comorbid medical and mental health conditions

STUDY OBJECTIVES

Intraindividual variability (IIV) in sleep may be a risk factor for disease above the influence of mean sleep. Associations between IIV in sleep and risk for a comprehensive set of common medical and mental health conditions have not been assessed in a representative sample.

METHODS

This study examined mean and IIV in total sleep time (TST), sleep quality (SQ), sleep efficiency (SE), and circadian midpoint (CM) in 771 adults recruited for an epidemiological study. Participants completed 14 days of sleep diaries to assess TST, SQ, SE, and CM, after which they reported on medical conditions and mental health symptoms. Data were analyzed using logistic regression, and models controlled for gender, body mass index, age, and race.

RESULTS

Lower mean TST, SQ, and SE were related to increased odds of having gastrointestinal problems, depression, and anxiety. IIV in TST was related to increased odds of having neurological, breathing, and gastrointestinal problems, as well as pain and depression; all results held controlling for mean sleep and adjusting for false discovery rate. IIV in SQ and SE was not associated with odds of having any medical or mental health conditions after adjusting for false discovery rate, nor was IIV in CM or mean CM.

CONCLUSIONS

Confirming previous research, mean TST, SQ, and SE are related to risk for gastrointestinal problems, depression, and anxiety. IIV in TST may be a unique facet of disturbed sleep that is associated with increased risk for a diverse cluster of medical and mental health conditions.

Validity of Actigraphy in Young Adults With Insomnia

Objective/Background: Actigraphy is an inexpensive and objective wrist-worn activity sensor that has been validated for the measurement of sleep onset latency (SOL), number of awakenings (NWAK), wake after sleep onset (WASO), total sleep time (TST), and sleep efficiency (SE) in both middle-aged and older adults with insomnia. However, actigraphy has not been evaluated in young adults. In addition, most previous studies compared actigraphy to in-lab polysomnography (PSG), but none have compared actigraphy to more ecologically valid ambulatory polysomnography.Participants: 21 young adults (mean age = 19.90 ± 2.19 years; n = 13 women) determined to have chronic primary insomnia through structured clinical interviews.Methods: Sleep diaries, actigraphy, and ambulatory PSG data were obtained over a single night to obtain measures of SOL, NWAK, WASO, time spent in bed after final awakening in the morning (TWAK), TST, and SE.Results: Actigraphy was a valid estimate of SOL, WASO, TST, and SE, based on significant correlations (r = 0.45 to 0.87), nonsignificant mean differences between actigraphy and PSG, and inspection of actigraphy bias from Bland Altman plots (SOL α = 1.52, WASO α = 7.95, TST α = -8.60, SE α = -1.38).Conclusions: Actigraphy was a valid objective measure of SOL, WASO, TST, and SE in a young adult insomnia sample, as compared to ambulatory PSG. Actigraphy may be a valid alternative for assessing sleep in young adults with insomnia when more costly PSG measures are not feasible.

Intraindividual variability in sleep and perceived stress in young adults

OBJECTIVES

Research suggests strong associations between habitual sleep parameters (eg, mean duration, timing, efficiency), perceived stress, and insomnia symptoms. The associations between intraindividual variability (IIV; night-to-night within-person variation) in sleep, perceived stress, and insomnia have not been explored. This study examined associations between IIV in subjectively and objectively determined sleep parameters and to perceived stress in young adults with and without insomnia.

DESIGN

Prospective longitudinal.

SETTING AND PARTICIPANTS

Participants were 149 college students (mean age = 20.2 [SD = 2.4], 59% female) either with insomnia (n = 81; 54%) or without insomnia (n = 68; 46%).

MEASUREMENTS

Participants completed 1 week of daily sleep diaries and actigraphy (to assess total sleep time [TST], sleep efficiency [SE], and circadian midpoint [CM]), the Perceived Stress Scale, and a diagnostic interview for determination of insomnia as part of a parent study.

RESULTS

Greater IIV in actigraphy-determined TST (but not SE or CM) was independently associated with greater perceived stress, regardless of insomnia status. Greater IIV in sleep diary-determined TST, SE, or CM was not associated with perceived stress. Insomnia status was the most robust predictor of elevated perceived stress. There was a significant interaction between IIV in sleep diary-determined TST and insomnia status on perceived stress: Only in those without insomnia was greater IIV in sleep diary-determined TST associated with higher perceived stress.

CONCLUSION

Maintaining a more consistent sleep duration may be associated with lower stress in college students. Future research is needed to clarify the directionality and implications of this association for treatment.

Insomnia and cognitive performance: A systematic review and meta-analysis

Cognitive performance has been extensively investigated in relation to insomnia, yet review of the literature reveals discrepant findings. The current study aimed to synthesize this literature with a systematic review and meta-analysis. 48 studies (k = 50 independent samples, n = 4539 total participants) met inclusion criteria. Omnibus meta-analysis revealed insomnia was associated with poorer overall cognitive performance (Hedge's g = -0.24, p < 0.001). Analyses by cognitive domain revealed insomnia was specifically associated with impairments in subjective cognitive performance (g = -0.35), and objective measures of perceptual function (g = -0.24), manipulation (g = -0.52) and retention/capacity in working memory (g = -0.30), complex attention (g = -0.36), alertness (g = -0.14), episodic memory (g = -0.29), and problem solving in executive functions (g = -0.39). Age, percent female, publication year, and insomnia measure did not consistently moderate findings. Approximately 44% of studies failed to use diagnostic criteria when categorizing insomnia and cognitive measures varied widely. This indicates a need for standardization of methods assessing insomnia and cognitive performance in research. Overall, findings from this meta-analysis indicate insomnia is associated with impairment in objective and subjective cognitive performance, highlighting the utility of treating insomnia to potentially improve cognitive outcomes.