Detailed Polysomnography in Australian Vietnam Veterans With and Without Posttraumatic Stress Disorder

The obstructive sleep apnoea endotypes are similar in elderly trauma-exposed veterans with and without diagnosed PTSD

BACKGROUND

Approximately 60% of veterans living with posttraumatic stress disorder (PTSD) experience obstructive sleep apnoea (OSA). Why OSA is so prevalent in individuals with PTSD remains unknown, though PTSD may influence the underlying endotypes known to cause OSA. We examined whether these endotypes (upper airway collapsibility, muscle compensation, loop gain, and the arousal threshold) differ between those with comorbid OSA and PTSD relative to their counterparts with OSA-only.

METHODS

Using the ventilatory flow pattern from diagnostic polysomnography, the OSA endotypes were measured in a retrospective cohort of 21 OSA patients with PTSD and 27 OSA-only patients. All participants were trauma exposed elderly male Australian Vietnam War veterans with mild-to-severe OSA (median Apnoea-Hypopnea index: 20.2 vs. 23.6 events/h). Age and BMI were similar between groups (70.7 vs. 71.7 years, and 28.4 vs. 28.4 kg/m2).

RESULTS

There were no significant differences in the OSA endotype traits between PTSD + OSA and OSA-only patients for upper airway collapsibility (76.68 [71.53-83.56] vs. 78.35 [72.81-83.82] %Veupnea, median [IQR]), muscle compensation (4.27 [0.34-9.18] vs. 5.41 [1.83-7.21] %Veupnea), loop gain (0.56(0.17) vs. 0.60(0.14)), and arousal threshold (135.76 [126.59-147.54] vs. 146.95 [128.64-151.28] %Veupnea).

CONCLUSION

The OSA endotypes in veterans with PTSD were similar to their trauma exposed OSA-only counterparts. PTSD appears to exert little influence on the OSA endotypes beyond the effect that age and trauma exposure may have. The aetiology of increased prevalence of OSA in PTSD remains unclear. Further work examining OSA endotypes using larger and more diverse samples is needed before robust conclusions can be made.

Effects of Antidepressants on Sleep in Post-traumatic Stress Disorder: An Overview of Reviews

Antidepressants are a commonly used, easily accessible, and overall safe treatment option for post-traumatic stress disorder (PTSD). The present review aims to evaluate the efficacy and safety of antidepressants in treating sleep disturbances in patients with PTSD. PubMed and the Cochrane Library were searched (July 2022) for systematic reviews and meta-analyses on the treatment of PTSD. Moreover, PubMed and ClinicalTrials.gov were searched for individual trials investigating the antidepressant treatment of PTSD (up to September 2022), and reference lists of all possibly relevant identified studies were screened. Sleep-related outcomes, i.e., total sleep time, sleep quality, dreams/ nightmares, insomnia, and somnolence, were extracted independently by at least two reviewers. Metaanalytic evaluations were performed wherever possible. 39 randomised controlled trials (RCTs) were identified; data from pooled analyses, reviews, and observational studies were used for antidepressants with a weak evidence base or when their findings were deemed important. Overall, scarce data exist on the effects of antidepressants on sleep outcomes among patients with PTSD. Some evidence may support the use of amitriptyline, nefazodone, paroxetine, and sertraline for improving sleep in patients with PTSD. Τhere was a meta-analytical trend indicating improvement of nightmares with fluoxetine, less insomnia with amitriptyline and more with brofaromine, as well as more somnolence with paroxetine vs. placebo, respectively. However, data from more than 1 RCT with a considerable number of patients were only available for paroxetine. Evidence is insufficient to draw safe conclusions. More and better-designed RCTs, with consistent reporting of sleep-related outcomes, are needed.

Metabotropic glutamate receptor function and regulation of sleep-wake cycles

Metabotropic glutamate (mGlu) receptors are the most abundant family of G-protein coupled receptors and are widely expressed throughout the central nervous system (CNS). Alterations in glutamate homeostasis, including dysregulations in mGlu receptor function, have been indicated as key contributors to multiple CNS disorders. Fluctuations in mGlu receptor expression and function also occur across diurnal sleep-wake cycles. Sleep disturbances including insomnia are frequently comorbid with neuropsychiatric, neurodevelopmental, and neurodegenerative conditions. These often precede behavioral symptoms and/or correlate with symptom severity and relapse. Chronic sleep disturbances may also be a consequence of primary symptom progression and can exacerbate neurodegeneration in disorders including Alzheimer's disease (AD). Thus, there is a bidirectional relationship between sleep disturbances and CNS disorders; disrupted sleep may serve as both a cause and a consequence of the disorder. Importantly, comorbid sleep disturbances are rarely a direct target of primary pharmacological treatments for neuropsychiatric disorders even though improving sleep can positively impact other symptom clusters. This chapter details known roles of mGlu receptor subtypes in both sleep-wake regulation and CNS disorders focusing on schizophrenia, major depressive disorder, post-traumatic stress disorder, AD, and substance use disorder (cocaine and opioid). In this chapter, preclinical electrophysiological, genetic, and pharmacological studies are described, and, when possible, human genetic, imaging, and post-mortem studies are also discussed. In addition to reviewing the important relationships between sleep, mGlu receptors, and CNS disorders, this chapter highlights the development of selective mGlu receptor ligands that hold promise for improving both primary symptoms and sleep disturbances.

Neurobiology of dream activity and effects of stimulants on dreams

The sleep-wake cycle is the result of the activity of a multiple neurobiological network interaction. Dreaming feature is one interesting sleep phenomena that represents sensorial components, mostly visual perceptions, accompanied with intense emotions. Further complexity has been added to the topic of the neurobiological mechanism of dreams generation by the current data that suggests the influence of drugs on dream generation. Here, we discuss the review on some of the neurobiological mechanism of the regulation of dream activity, with special emphasis on the effects of stimulants on dreaming.

Investigation of C-reactive protein and AIM2 methylation as a marker for PTSD in Australian Vietnam veterans

Chronic inflammation is a key factor in symptomology and comorbidities of post-traumatic stress disorder (PTSD). Levels of a proinflammatory marker, C-reactive protein (CRP) are increased in individuals with PTSD but it is not clear if this is due to trauma exposure or PTSD. Our study aimed to assess the relationship between serum CRP levels, CRP SNPs, methylation, mRNA expression and PTSD in a homogenous trauma exposed Australian Vietnam veteran cohort. We hypothesized that decreased DNA methylation would be associated with increased gene expression and increased peripheral CRP levels in PTSD patients and that this would be independent of trauma. Participants were 299 Vietnam veterans who had all been exposed to trauma and approximately half were diagnosed with PTSD. We observed higher levels of serum CRP in the PTSD group compared to the non-PTSD group but after controlling for BMI and triglycerides the association did not remain significant. No association was found between CRP SNPs and PTSD or CRP levels. Absent in Melanoma 2 (AIM2) which is a mediator of inflammatory response and a determinant of CRP levels was analysed for DNA methylation and mRNA expression. We observed a trend level association between PTSD and AIM2 methylation after controlling for age, smoking, triglycerides, BMI and cell types. There was no significant interaction between PTSD and CRP levels on AIM2 methylation after controlling for covariates. We observed that as AIM2 methylation levels decreased, AIM2 mRNA expression increased. Elevated CRP levels were associated with AIM2 mRNA in the trauma exposed cohort but there was no significant interaction effect with PTSD. Our results could not confirm that CRP is a marker of PTSD independent of trauma in this group of older veterans. CRP may be a broad marker of disease risk, or a marker of PTSD in younger cohorts than those in this study.

Cross-Lagged Relationships Between Insomnia and Posttraumatic Stress Disorder in Treatment-Receiving Veterans

Insomnia is a risk factor for the development of posttraumatic stress disorder (PTSD) while it is also plausible that PTSD symptoms can maintain insomnia symptoms. The present study examined longitudinal bidirectional relationships between insomnia and PTSD symptoms in treatment-seeking veterans. Participants were 693 ex-serving members of the Australian Defence Force who participated in an accredited, hospital-based outpatient PTSD program. Participants completed self-reported assessments of PTSD and insomnia symptoms at four time points: intake, discharge, 3-month, and 9-months posttreatment follow-up. Cross-lagged pathway analyses indicated significant bi-directional pathways between insomnia symptoms and PTSD symptoms at most time points. A final cross-lagged model between insomnia symptoms and the PTSD symptom clusters indicated that the PTSD symptom paths on insomnia symptoms, between intake and discharge, were attributable to reexperiencing PTSD symptoms. In contrast, across posttreatment follow-up time points there were significant paths of insomnia symptoms on all PTSD symptom clusters except from insomnia at 3-months to avoidance symptom at 9-months. PTSD symptoms and insomnia symptoms have bidirectional associations over time that may lead to the mutual maintenance or exacerbation of each condition following PTSD treatment. Where residual insomnia symptoms are present post-treatment, a sleep-focussed intervention is indicated and a sequenced approach to treatment recommended.

Differences in sleep apnea among veterans with PTSD and other mental health conditions

The current study compared polysomnography results of 200 consecutive VA sleep clinic referrals with PTSD, other mental health diagnoses (OTHMH), and no mental health diagnoses (NOMH). There were 59 (29.5%) NOMH cases, 62 (31.0%) PTSD cases, and 79 (39.5%) OTHMH cases. SA was diagnosed in 105 cases (52.5%), and rates of SA diagnosis did not differ by MH diagnosis. PTSD SA cases were younger than NOMH cases. NOMH cases had less sleep and higher apnea-hypopnea index than OTHMH cases. PTSD cases were not different on any sleep variable, hypertension frequency, or body-mass index.

Epidemiology of disturbing dreams in a diverse US sample

STUDY OBJECTIVES

Disturbing dreams are a common complaint among trauma survivors, but little epidemiological research exists to document the frequency in the general population. In addition, information about their occurrence in diverse adults is lacking.

METHODS

Using the Collaborative Psychiatric Epidemiology Surveys we had the unique opportunity to examine disturbing dreams in a diverse sample of adults in the US. Disturbing dreams were measured in three different variables including trauma dreams, dreams of the worst event, and dreams of separation. A fourth variable was created to assess for any disturbing dream reported across the three categories.

RESULTS

Disturbing dream prevalence varied in the overall sample (N = 20,013) based on the assessment question. Dreams of trauma was 2.01% in the overall sample, dreams of the worst event was 7.21% and dreams of separation was 1.73%. Prevalence rates of all dream variables varied by racial and ethnic group membership, gender, and age. Odds ratios were also calculated for the three variables of interest by racial and ethnic group with significant differences emerging. Women had significantly higher rates of disturbing dreams in all variables assessed (p < 0.01). Older adults reported significantly lower rates of disturbing dreams compared to younger and middle-aged adults (p < 0.001).

CONCLUSIONS

This study establishes prevalence rates for disturbing dreams in a diverse sample of US adults. Understanding the prevalence can aid in reducing barriers to care for evidence-based treatments currently underutilized.

Sleep in posttraumatic stress disorder: A systematic review and meta-analysis of polysomnographic findings

Polysomnographic studies have been performed to examine sleep abnormalities in posttraumatic stress disorder (PTSD), but clear associations between PTSD and sleep disturbances have not been established. A systematic review of the evidence examining the polysomnographic changes in PTSD patients compared with controls was conducted using MEDLINE, EMBASE, All EBM databases, PsycINFO, and CINAHL databases. Meta-analysis was undertaken where possible. The searches identified 34 studies, 31 of which were appropriate for meta-analysis. Pooled results indicated decreased total sleep time, slow wave sleep and sleep efficiency, and increased wake time after sleep onset in PTSD patients compared with healthy controls. PTSD severity was associated with decreased sleep efficiency and slow wave sleep percentage. Rapid eye movement (REM) sleep percentage was significantly decreased in PTSD patients compared with controls in studies including participants with mean age below 30 y, but not in studies with other mean age groups (30-40 y and >40 y). Our study shows that polysomnographic abnormalities are present in PTSD. Sex, age, PTSD severity, type of controls, medication status, adaptation night, polysomnographic scoring rules and study location are several of the demographic, clinical and methodological factors that contribute to heterogeneity between studies.

Comparison of Sleep Patterns in Vietnam Veterans With and Without Posttraumatic Stress Disorder Using Wrist Actigraphy

STUDY OBJECTIVES

Disturbed sleep is a hallmark feature of posttraumatic stress disorder (PTSD). However, few studies have examined sleep objectively in individuals with PTSD compared to trauma-exposed controls. This study used wrist actigraphy to measure and compare sleep patterns in trauma-exposed Australian Vietnam veterans (VV) with and without PTSD.

METHODS

Trauma-exposed Australian VV with and without PTSD were recruited from the PTSD Initiative. VV wore wrist accelerometers over 14 days and completed daily sleep diaries. Sleep parameters were compared between groups including sleep latency (SL), time in bed (TIB), total sleep time (TST), wake after sleep onset (WASO), and movement index (MI). Night-to-night and overall within-individual variability were assessed by root mean squared successive differences and comparison of individual standard deviations. Correlations between sleep diary (self-reported) and wrist actigraphy (objective) variables were also assessed.

RESULTS

A total of 40 male VV (20 with PTSD) participated in the study. We found no difference in sleep patterns determined by wrist actigraphy between groups with the exception of reduced SL in VV with PTSD (3.9 ± 0.9 versus 4.9 ± 1.4 minutes, P < .05). Overall within-individual variability was significantly greater in VV with PTSD for TIB, TST, WASO, and MI. Self-reported and objective TST and WASO were more strongly correlated in VV without PTSD than those with PTSD.

CONCLUSIONS

Although there were no significant differences in sleep parameters, VV with PTSD had increased within-individual overall sleep variability and reduced correlation between self-reported and objective sleep parameters compared to trauma-exposed controls. Further evaluation of extended sleep patterns by actigraphy in VV with PTSD is warranted.