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 ( ß = -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.

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.

Posttraumatic stress symptoms and positive autobiographical memory characteristics in everyday life.

Individuals with posttraumatic stress symptoms (PTSS) report difficulties engaging with positive autobiographical memories. Extending this line of research, we examined daily-level concurrent and lagged associations between PTSS severity and positive memory characteristics (vividness, coherence, accessibility, time perspective, sensory details, visual perspective, emotional intensity, sharing, distancing, and valence). The sample included 88 trauma survivors (Mage = 39.89 years, 59.1% female) who completed seven daily measures of PTSS and positive memory characteristics. Multilevel models examined concurrent and lagged associations between PTSS severity and positive memory characteristics. The results indicated that days with higher PTSS severity were associated with less accessibility, ß = -.21, p < .001; less visual perspective, ß = -0.13, p = .034; and lower positive valence of the memory, ß = -.19, p = .003, as well as more emotional intensity associated with, ß = .13, p = .041, and more distancing from, ß = .21, p < .001, the memory. Supplemental lagged analyses indicated that higher previous-day PTSS severity was associated with more next-day distancing from, ß = .15, p = .042, and sensory details of, ß = .17, p = .016, the memory. Findings suggest that individuals with more severe PTSS have difficulties accessing positively valenced memories from a first-person perspective, are more distant from the recalled positive memory, and report more emotional intensity when retrieving the memory. Thus, improving access to and reducing distance from positive autobiographical memories, as well as addressing emotional intensity surrounding the retrieval of these memories, may be potential clinical targets for PTSS interventions.

Psychometric Evaluation of the Insomnia Severity Index in Nurses.

OBJECTIVES: Examine psychometric properties of the Insomnia Severity Index (ISI) in a sample of nurses. METHOD: In a sample of day shift nurses (N = 289), a confirmatory factor analysis (CFA), convergent and discriminant validity analyses, and a test-retest reliability analysis were performed. RESULTS: CFA showed that a two-factor model provided the best fit. The ISI had moderate to poor convergent validity with sleep diary parameters, and moderate convergent validity with the Sleep Condition Indicator (r = -.66), Pittsburgh Sleep Quality Index (r = .66), and PROMIS Sleep-Related Impairment measure (r = .67). The ISI demonstrated good discriminant validity with the measures Composite Scale of Morningness (r = -.27), Nightmares Disorder Index (r = .25), PTSD Checklist for DSM-5 (sleep items removed; r = .32), and Perceived Stress Scale (r = .43). The ISI had weaker discriminant validity with the PHQ-9 (r = .69) and Generalized Anxiety Disorder Screener (r = .51). The ISI demonstrated a good test-retest reliability (ICCs = .74-.88). CONCLUSIONS: The ISI is a psychometrically strong measure for the assessment of insomnia severity in day shift nurses. Overlap with psychological symptoms, primarily anxiety and depression, suggests caution while interpreting these constructs.

Alcohol Use Predicts Longer But More Fragmented Sleep: A Daily Diary Study of Alcohol, Sleep, and PTSD in Nurses.

BACKGROUND: Due to the demanding nature of their profession, nurses are at risk of experiencing irregular sleep patterns, substance use, and fatigue. Evidence supports a reciprocal relationship between alcohol use and sleep disturbances; however, no research has examined such a link in a sample of nurses. One factor that may further impact the dynamic between alcohol and sleep patterns is posttraumatic stress disorder (PTSD) symptoms. We investigated the daily bidirectional associations between alcohol use and several sleep domains (i.e., self-report and actigraphy-determined sleep), and moderation by baseline PTSD symptom severity. METHOD: Over a 14-day period, 392 nurses (92% female; 78% White) completed sleep diaries and actigraphy to assess alcohol use and sleep patterns. Within-person bidirectional associations between alcohol and sleep were examined using multilevel models, with symptoms of PTSD as a cross-level moderator. RESULTS: Daily alcohol use (i.e., ≥ 1 alcoholic beverage; 25.76%) was associated with shorter self-reported sleep onset latency (b = -4.21, p = .003) but longer self-reported wake after sleep onset (b = 2.36, p = .009). Additionally, days with any alcohol use were associated with longer self-reported sleep duration (b = 15.60, p = .006) and actigraphy-determined sleep duration (b = 10.06, p = .037). No sleep variables were associated with next-day alcohol use. Bidirectional associations between alcohol consumption and sleep were similar regardless of baseline PTSD symptoms. CONCLUSION: Our results suggested that on days when nurses drank alcohol, they experienced longer but also more fragmented sleep.

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 (ß = -0.05, p = .039). In addition, greater stress reactivity to sleep duration (ß = -0.08, p = .017) and sleep efficiency (ß = -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.

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 may contribute to an individual's risk of developing of psychological disorders, such as depression, anxiety, and insomnia. It is possible that individuals with high sleep-stress reactivity are more likely to experience long-term functional impairment (e.g., impairment in social relationships and interpersonal functioning)­a predisposing factor for psychological disorders, yet this pathway has not been explored. Therefore, we examined associations between sleep-stress reactivity and changes in functional impairment across a 1-year period in a large sample of 9/11 World Trade Center responders. The study results suggest that 9/11 World Trade Center responders who are more reactive to daily fluctuations in stress and sleep have poorer interpersonal relationships and social functioning. Identifying individuals with high sleep-stress reactivity who could benefit from preventative treatment may foster better social integration.

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.

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.

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 (ß = 0.14) and vice versa (ß = 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.

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.

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.

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.

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-1ß), 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-1ß. 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.

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.

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-1ß), 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-1ß reactivity to stress (b = 0.41, p=.007). For every 1-unit increase in study sample average BMI, effect sizes for IL-1ß 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.

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 (ß = -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 (ß = 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.

Nightmares and Insomnia in the US National Guard: Mental and Physical Health Correlates.

BACKGROUND: Nightmares and insomnia are significant concerns that commonly co-occur with each other and with other health disorders. Limited research has examined the unique and shared aspects of insomnia and nightmares, and little is known about sleep in US National Guard personnel. This study sought to determine the prevalence and psychosocial correlates of nightmares with and without insomnia in US National Guard personnel. METHOD: National Guard personnel (N = 841) completed an online survey and were classified as having nightmares only, insomnia only, both, or neither, using a minimum nightmare frequency of "less than once a week" and an Insomnia Severity Index cutoff of ≥ 15. Analyses examined differences in demographics, physical health, and psychosocial variables and in the prevalence of nightmares and insomnia in personnel with physical and mental health problems. RESULTS: In this sample, 32% reported nightmares only, 4% reported insomnia only, and 12% reported both. Those in the youngest age group (18-21) were more likely to have no nightmares or insomnia. Those with both nightmares and insomnia had more deployments. Nightmares and insomnia were associated with poorer physical and mental health and greater prevalence of comorbid physical and mental health conditions. Personnel with both insomnia and nightmares reported the greatest severity of comorbid conditions. CONCLUSION: US National Guard personnel with nightmares and/or insomnia reported worse mental and physical health impairment than those without these conditions. Personnel may benefit from screening for nightmares and insomnia and referrals for evidence-based treatment.

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.

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-1ß. 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-1ß (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.