Subjective versus objective sleep in Vietnam combat veterans hospitalized for PTSD

REM Sleep Behavior Disorder among Veterans with and without Post-Traumatic Stress Disorder

OBJECTIVE

Among veterans, the prevalence of rapid eye movement sleep behavior disorder (RBD) is higher than among the general population, and some evidence suggests that this is related to post-traumatic stress disorder (PTSD). The purpose of this study was to determine whether the frequency of RBD differs depending on the presence of PTSD or trauma.

METHODS

Patients who underwent nocturnal polysomnography (PSG) and sleep-related questionnaire surveys at the Veteran Health Service Medical Center were reviewed retrospectively. Based on patients with PTSD (n=20; 100% male; 67.9±8.5 years of age), we matched patients exposed to trauma without PTSD (n23; 100% male; age 64.0±13.4) and patients without trauma (n=21; 100% male; age 59.86±10.9).

RESULTS

PTSD patients reported dream enactment behavior more than the trauma-exposed group without PTSD or the control group (p=0.006). After adjusting for age, there were more RBD patients in the PTSD group than in the trauma exposed group (p=0.049).

CONCLUSION

The results showed that RBD occurred significantly more in veterans with PTSD than those exposed to trauma, which suggests that there may be a pathophysiological association between PTSD and RBD.

Objective Characterization of Activity, Sleep, and Circadian Rhythm Patterns Using a Wrist-Worn Actigraphy Sensor: Insights Into Posttraumatic Stress Disorder

BACKGROUND

Wearables have been gaining increasing momentum and have enormous potential to provide insights into daily life behaviors and longitudinal health monitoring. However, to date, there is still a lack of principled algorithmic framework to facilitate the analysis of actigraphy and objectively characterize day-by-day data patterns, particularly in cohorts with sleep problems.

OBJECTIVE

This study aimed to propose a principled algorithmic framework for the assessment of activity, sleep, and circadian rhythm patterns in people with posttraumatic stress disorder (PTSD), a mental disorder with long-lasting distressing symptoms such as intrusive memories, avoidance behaviors, and sleep disturbance. In clinical practice, these symptoms are typically assessed using retrospective self-reports that are prone to recall bias. The aim of this study was to develop objective measures from patients' everyday lives, which could potentially considerably enhance the understanding of symptoms, behaviors, and treatment effects.

METHODS

Using a wrist-worn sensor, we recorded actigraphy, light, and temperature data over 7 consecutive days from three groups: 42 people diagnosed with PTSD, 43 traumatized controls, and 30 nontraumatized controls. The participants also completed a daily sleep diary over 7 days and the standardized Pittsburgh Sleep Quality Index questionnaire. We developed a novel approach to automatically determine sleep onset and offset, which can also capture awakenings that are crucial for assessing sleep quality. Moreover, we introduced a new intuitive methodology facilitating actigraphy exploration and characterize day-by-day data across 49 activity, sleep, and circadian rhythm patterns.

RESULTS

We demonstrate that the new sleep detection algorithm closely matches the sleep onset and offset against the participants' sleep diaries consistently outperforming an existing open-access widely used approach. Participants with PTSD exhibited considerably more fragmented sleep patterns (as indicated by greater nocturnal activity, including awakenings) and greater intraday variability compared with traumatized and nontraumatized control groups, showing statistically significant (P<.05) and strong associations (|R|>0.3).

CONCLUSIONS

This study lays the foundation for objective assessment of activity, sleep, and circadian rhythm patterns using passively collected data from a wrist-worn sensor, facilitating large community studies to monitor longitudinally healthy and pathological cohorts under free-living conditions. These findings may be useful in clinical PTSD assessment and could inform therapy and monitoring of treatment effects.

The effects of prazosin on sleep disturbances in post-traumatic stress disorder: a systematic review and meta-analysis

BACKGROUND

Nightmares are a highly prevalent and distressing feature of post-traumatic stress disorder (PTSD). Previous studies have reached mixed conclusions regarding the effects of prazosin on nightmares, sleep quality, and overall PTSD symptoms in patients with PTSD.

METHODS

MEDLINE, EMBASE, all EBM databases, PsycIFNO, and CINAHL were systematically searched from inception date to October 2018 for randomized clinical trials that included reporting of nightmares, sleep quality or overall PTSD symptoms. The analysis included data from eight trials involving 286 PTSD patients in the prazosin group and 289 PTSD patients in the placebo group.

RESULTS

In our meta-analysis, prazosin resulted in a statistically significant improvement in nightmares (standardized mean difference (SMD) = -1.13, 95% confidence interval (CI) = -1.91 to -0.36), but was not more beneficial than placebo for overall PTSD symptoms (SMD = -0.45, 95% CI = -0.95 to 0.05) and sleep quality (SMD = -0.44, 95% CI = -1.44 to 0.55). In terms of acceptability, there was no significant difference between the prazosin group and the placebo group with respect to discontinuation for all causes (odds ratio (OR) = 1.00, 95% CI = 0.62-1.62). In conclusion, the use of prazosin was associated with an improvement of nightmare symptoms.

CONCLUSION

Our findings indicate that additional studies are needed before considering downgrading the use of prazosin in the treatment of nightmares in patients with PTSD.

Impact of Traumatic Stress on Sleep and Management Options in Women

After exposure to traumatic stress, women are at greater risk than men for developing symptoms of some psychiatric disorders, including insomnia and nightmares. Sleep disturbance is one of the most refractory symptoms of posttraumatic stress disorder. Women were included in a few studies that examined efficacy of psychological or pharmacologic interventions for trauma-related sleep disturbances. Studies demonstrated preliminary evidence for efficacy of cognitive behavioral therapy for insomnia, imagery rehearsal therapy, and combinations of these techniques in treating insomnia and nightmares in trauma-exposed women. Prazosin as an adjunct to ongoing treatment is a potentially efficacious strategy for treating trauma-related nightmares in women.

In-Home Sleep Recordings in Military Veterans With Posttraumatic Stress Disorder Reveal Less REM and Deep Sleep <1 Hz

Veterans with posttraumatic stress disorder (PTSD) often report suboptimal sleep quality, often described as lack of restfulness for unknown reasons. These experiences are sometimes difficult to objectively quantify in sleep lab assessments. Here, we used a streamlined sleep assessment tool to record in-home 2-channel electroencephalogram (EEG) with concurrent collection of electrodermal activity (EDA) and acceleration. Data from a single forehead channel were transformed into a whole-night spectrogram, and sleep stages were classified using a fully automated algorithm. For this study, 71 control subjects and 60 military-related PTSD subjects were analyzed for percentage of time spent in Light, Hi Deep (1-3 Hz), Lo Deep (<1 Hz), and rapid eye movement (REM) sleep stages, as well as sleep efficiency and fragmentation. The results showed a significant tendency for PTSD sleepers to spend a smaller percentage of the night in REM (p < 0.0001) and Lo Deep (p = 0.001) sleep, while spending a larger percentage of the night in Hi Deep (p < 0.0001) sleep. The percentage of combined Hi+Lo Deep sleep did not differ between groups. All sleepers usually showed EDA peaks during Lo, but not Hi, Deep sleep; however, PTSD sleepers were more likely to lack EDA peaks altogether, which usually coincided with a lack of Lo Deep sleep. Linear regressions with all subjects showed that a decreased percentage of REM sleep in PTSD sleepers was accounted for by age, prazosin, SSRIs and SNRIs (p < 0.02), while decreased Lo Deep and increased Hi Deep in the PTSD group could not be accounted for by any factor in this study (p < 0.005). Linear regression models with only the PTSD group showed that decreased REM correlated with self-reported depression, as measured with the Depression, Anxiety, and Stress Scales (DASS; p < 0.00001). DASS anxiety was associated with increased REM time (p < 0.0001). This study shows altered sleep patterns in sleepers with PTSD that can be partially accounted for by age and medication use; however, differences in deep sleep related to PTSD could not be linked to any known factor. With several medications [prazosin, selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs); p < 0.03], as well as SSRIs were associated with less sleep efficiency (b = -3.3 ± 0.95; p = 0.0005) and more sleep fragmentation (b = -1.7 ± 0.51; p = 0.0009). Anti-psychotics were associated with less sleep efficiency (b = -4.9 ± 1.4; p = 0.0004). Sleep efficiency was negatively impacted by SSRIs, antipsychotic medications, and depression (p < 0.008). Increased sleep fragmentation was associated with SSRIs, SNRIs, and anxiety (p < 0.009), while prazosin and antipsychotic medications correlated with decreased sleep fragmentation (p < 0.05).

The impact of posttraumatic stress disorder versus resilience on nocturnal autonomic nervous system activity as functions of sleep stage and time of sleep

Posttraumatic stress disorder (PTSD) has been associated with sleep disturbances including alterations in sleep stages and recently, elevated nocturnal autonomic nervous system (ANS) arousal (i.e., dominance of the sympathetic nervous system over the parasympathetic nervous system). Data suggest that sleep contributes to the regulation of ANS activity. In our previous ambulatory heart rate variability (HRV) monitoring study, strong relationships between sleep and nocturnal ANS activity in resilient participants (i.e., individuals who had never had PTSD despite exposure to high-impact trauma) were not seen with PTSD. In this study, we examined the impact of PTSD vs. resilience on ANS activity as a function of sleep stage and time of sleep. Participants (age 18-35) with current PTSD (n=38) and resilience (n=33) completed two overnight polysomnography recordings in a lab setting. The second night electrocardiogram was analyzed for frequency domain HRV parameters and heart rate within rapid-eye-movement (REM) and non-REM (NREM) sleep periods. Results indicated that ANS arousal indexed by HRV was greater during REM compared with NREM sleep and that the REM-NREM difference was greater in the PTSD than in the resilient participants. This effect of PTSD was reduced to non-significance when analyses controlled for REM sleep percentage, which was lower with PTSD. Exploratory analyses revealed that the REM-NREM difference in HRV was correlated with REM sleep percentage in resilient participants, but not with PTSD. In contrast with our data from home settings, the present study did not find increased overall nocturnal ANS arousal with PTSD. Analyses did reveal higher heart rate during initial NREM sleep with more rapid decline over the course of NREM sleep with PTSD compared with resilience. Findings suggest that elevated ANS arousal indexed by heart rate with PTSD is specific to the early part of sleep and possible impairment in regulating ANS activity with PTSD related to REM sleep.

Sleep and mental disorders: A meta-analysis of polysomnographic research

Investigating sleep in mental disorders has the potential to reveal both disorder-specific and transdiagnostic psychophysiological mechanisms. This meta-analysis aimed at determining the polysomnographic (PSG) characteristics of several mental disorders. Relevant studies were searched through standard strategies. Controlled PSG studies evaluating sleep in affective, anxiety, eating, pervasive developmental, borderline and antisocial personality disorders, attention-deficit-hyperactivity disorder (ADHD), and schizophrenia were included. PSG variables of sleep continuity, depth, and architecture, as well as rapid-eye movement (REM) sleep were considered. Calculations were performed with the "Comprehensive Meta-Analysis" and "R" software. Using random effects modeling, for each disorder and each variable, a separate meta-analysis was conducted if at least 3 studies were available for calculation of effect sizes as standardized means (Hedges' g). Sources of variability, that is, sex, age, and mental disorders comorbidity, were evaluated in subgroup analyses. Sleep alterations were evidenced in all disorders, with the exception of ADHD and seasonal affective disorders. Sleep continuity problems were observed in most mental disorders. Sleep depth and REM pressure alterations were associated with affective, anxiety, autism and schizophrenia disorders. Comorbidity was associated with enhanced REM sleep pressure and more inhibition of sleep depth. No sleep parameter was exclusively altered in 1 condition; however, no 2 conditions shared the same PSG profile. Sleep continuity disturbances imply a transdiagnostic imbalance in the arousal system likely representing a basic dimension of mental health. Sleep depth and REM variables might play a key role in psychiatric comorbidity processes. Constellations of sleep alterations may define distinct disorders better than alterations in 1 single variable. (PsycINFO Database Record

SLEEP AND TREATMENT OUTCOME IN POSTTRAUMATIC STRESS DISORDER: RESULTS FROM AN EFFECTIVENESS STUDY

BACKGROUND

Most patients with posttraumatic stress disorder (PTSD) suffer from sleep problems. Concerns have been raised about possible detrimental effects of sleep problems on the efficacy of psychological treatments for PTSD. In this study, we investigated the relation of session-to-session changes in PTSD symptoms and sleep, and tested whether sleep problems predicted poorer short- and long-term treatment outcome.

METHODS

Self-reported sleep quality, sleep duration, and PTSD symptoms were assessed weekly in a consecutive sample of 246 patients who received cognitive therapy for PTSD (CT-PTSD; Ehlers & Clark, 2000), and at follow-up (mean = 247 days posttreatment). Additionally, moderating effects of medication use and comorbid depression were assessed.

RESULTS

Sleep and PTSD symptoms improved in parallel. The relation was moderated by depression: Sleep problems at the start of therapy did not predict improvement in PTSD symptoms during treatment for patients without comorbid depression. Patients with comorbid depression, however, showed less rapid decreases in PTSD symptoms, but comparable overall outcome, if their sleep quality was poor. Residual sleep problems at the end of treatment did not predict PTSD symptoms at follow-up once residual PTSD symptoms were taken into account.

CONCLUSIONS

CT-PTSD leads to simultaneous improvement in sleep and PTSD symptoms. Sleep problems may reduce the speed of recovery in PTSD patients with comorbid depression. For these patients, additional treatment sessions are indicated to achieve comparable outcomes, and additional interventions targeting sleep may be beneficial. For those without comorbid depression, self-reported sleep problems did not interfere with response to trauma-focused psychological treatment.

Objective and subjective measurement of sleep disturbance in female trauma survivors with posttraumatic stress disorder

Sleep disturbance may be the most often endorsed symptom of posttraumatic stress disorder (PTSD). Much of this research is based on subjective reports from trauma survivors; however, objective measures of sleep-related impairment have yielded findings inconsistent with self-report data. More studies investigating subjective and objective assessments concordantly are needed to understand sleep impairment in PTSD. The current study examined PTSD-related sleep disturbance in a female interpersonal violence cohort with full PTSD diagnoses (N=51) assessing subjective (global and daily diary measures) and objective (actigraphy) sleep measures concurrently. PTSD severity was positively associated with global, subjective reports of sleep impairment and insomnia. Subjective measures of sleep (including global sleep impairment, insomnia, and daily sleep diary reports of total sleep time, sleep efficiency, and sleep onset latency) were moderately to strongly correlated. However, no significant correlations between subjective and objective reports of sleep impairment were found in this cohort. Analyses demonstrated an overall elevation in subjectively reported sleep impairment when compared to objective measurement assessed concurrently. Findings demonstrate a lack of agreement between subjective and objective measurements of sleep in a PTSD-positive female cohort, suggesting objective and subjective sleep impairments are distinct sleep parameters that do not necessarily directly co-vary.

Sleep disturbances, TBI and PTSD: Implications for treatment and recovery

Post-Traumatic Stress Disorder (PTSD), traumatic brain injury (TBI), and sleep problems significantly affect recovery and functional status in military personnel and Veterans returning from combat. Despite recent attention, sleep is understudied in the Veteran population. Few treatments and rehabilitation protocols target sleep, although poor sleep remains at clinical levels and continues to adversely impact functioning even after the resolution of PTSD or mild TBI symptoms. Recent developments in non-pharmacologic sleep treatments have proven efficacious as stand-alone interventions and have potential to improve treatment outcomes by augmenting traditional behavioral and cognitive therapies. This review discusses the extensive scope of work in the area of sleep as it relates to TBI and PTSD, including pathophysiology and neurobiology of sleep; existing and emerging treatment options; as well as methodological issues in sleep measurements for TBI and PTSD. Understanding sleep problems and their role in the development and maintenance of PTSD and TBI symptoms may lead to improvement in overall treatment outcomes while offering a non-stigmatizing entry in mental health services and make current treatments more comprehensive by helping to address a broader spectrum of difficulties.

Diagnosis and management of sleep disorders in posttraumatic stress disorder:a review of the literature

OBJECTIVE

International and societal conflicts and natural disasters can leave physical and mental scars in people who are directly affected by these traumatic experiences. Posttraumatic stress disorder (PTSD) is the clinical manifestation of these experiences in the form of re-experiencing the trauma, avoidance of trauma-related stimuli, and persistent symptoms of hyperarousal. There is growing evidence that sleep disruption that occurs following trauma exposure may in fact contribute to the pathophysiology of PTSD and poor clinical outcomes. The purpose of this review is to highlight the importance of recognition and management of sleep disorders in patients with PTSD.

DATA SOURCES

English-language, adult research studies published between 1985 and April 2014 were identified via the PubMed database. The search terms used were PTSD AND sleep disorders.

STUDY SELECTION

The search identified 792 original and review articles. Of these, 53 articles that discussed or researched sleep disorders in PTSD were selected. Fourteen randomized controlled trials of therapy for PTSD are included in this review.

RESULTS

Impaired sleep is a common complaint mainly in the form of nightmares and insomnia among people with PTSD. Sleep apnea and periodic limb movement disorder are particularly prevalent in patients with PTSD and, yet, remain unrecognized. Although selective serotonin reuptake inhibitors are effective in improving PTSD global symptoms, they have a variable and modest effect on sleep disorder symptoms. Cognitive-behavioral treatment targeted to sleep and/or the use of the centrally acting selective α1 antagonist prazosin have been more successful in treating insomnia and nightmares in PTSD than other classes of medications. In view of the high occurrence of sleep apnea and periodic leg movement disorder, a thorough sleep evaluation and treatment are warranted.

CONCLUSIONS

Patients with PTSD have a high prevalence of sleep disorders and should be queried for insomnia, nightmares, periodic limb movement disorder, and sleep-disordered breathing.

Subjectively and objectively measured sleep with and without posttraumatic stress disorder and trauma exposure

STUDY OBJECTIVES

Although reports of sleep disturbances are common among individuals with posttraumatic stress disorder (PTSD), results of polysomnographic (PSG) studies have inconsistently documented abnormalities and have therefore suggested "sleep state misperception." The authors' study objectives were to compare sleep parameters measured objectively and subjectively in the laboratory and at home in civilians with and without trauma exposure and PTSD.

DESIGN

Cross-sectional study.

SETTING

PSG recordings in a sleep laboratory and actigraphic recordings in participants' homes.

PARTICIPANTS

One hundred three urban-residing African Americans with and without trauma exposure and PTSD who participated in a larger study.

INTERVENTIONS

N/A.

MEASUREMENTS

Sleep parameters (total sleep time [TST], sleep onset latency [SOL], and wake after sleep onset [WASO]) were assessed using laboratory PSG and home actigraphy. A sleep diary was completed in the morning after PSG and actigraphy recordings. Habitual TST, SOL, and WASO were assessed using a sleep questionnaire. The Clinician Administered PTSD Scale was administered to assess participants' trauma exposure and PTSD diagnostic status.

RESULTS

Participants, regardless of their trauma exposure/PTSD status, underestimated WASO in the diary and questionnaire relative to actigraphy and overestimated SOL in the diary relative to PSG. Among participants with current PTSD, TST diary estimates did not differ from the actigraphy measure in contrast with those without current PTSD who overestimated TST. No other significant group differences in discrepancies between subjective and objective sleep measures were found.

CONCLUSIONS

Discrepancies between subjectively and objectively measured sleep parameters were not associated with trauma exposure or PTSD. This challenges prior assertions that individuals with PTSD overreport their sleep disturbances.

Sleep-specific mechanisms underlying posttraumatic stress disorder: integrative review and neurobiological hypotheses

Posttraumatic stress disorder (PTSD) is a prevalent disorder that is associated with poor clinical and health outcomes, and considerable health care utilization and costs. Recent estimates suggest that 5-20% of military personnel who serve in current conflicts in Iraq and Afghanistan meet diagnostic criteria for PTSD. Clinically, sleep disturbances are core features of PTSD that are often resistant to first-line treatments, independently contribute to poor daytime functioning, and often require sleep-focused treatments. Physiologically, these observations suggest that PTSD is partially mediated by sleep disruption and its neurobiological correlates that are not adequately addressed by first-line treatments. However, polysomnographic studies have provided limited insights into the neurobiological underpinnings of PTSD during sleep. There is an urgent need to apply state-of-the-science sleep measurement methods to bridge the apparent gap between the clinical significance of sleep disturbances in PTSD and the limited understanding of their neurobiological underpinnings. Here, we propose an integrative review of findings derived from neurobiological models of fear conditioning and fear extinction, PTSD, and sleep-wake regulation, suggesting that the amygdala and medial prefrontal cortex can directly contribute to sleep disturbances in PTSD. Testable hypotheses regarding the neurobiological underpinnings of PTSD across the sleep-wake cycle are offered.

Sleep disturbances in patients with post-traumatic stress disorder: epidemiology, impact and approaches to management

Subjective reports of sleep disturbance indicate that 70-91% of patients with post-traumatic stress disorder (PTSD) have difficulty falling or staying asleep. Nightmares are reported by 19-71% of patients, depending on the severity of their PTSD and their exposure to physical aggression. Objective measures of sleep disturbance are inconsistent, with some studies that used these measures indicating poor sleep and others finding no differences compared with non-PTSD controls. Future research in this area may benefit from examining measures of instability in the microstructure of sleep. Additionally, recent findings suggest that sleep disordered breathing (SDB) and sleep movement disorders are more common in patients with PTSD than in the general population and that these disorders may contribute to the brief awakenings, insomnia and daytime fatigue in patients with PTSD. Overall, sleep problems have an impact on the development and symptom severity of PTSD and on the quality of life and functioning of patients. In terms of treatments, SSRIs are commonly used to treat PTSD, and evidence suggests that they have a small but significant positive effect on sleep disruption. Studies of serotonin-potentiating non-SSRIs suggest that nefazodone and trazodone lead to significant reductions in insomnia and nightmares, whereas cyproheptadine may exacerbate sleep problems in patients with PTSD. Prazosin, a centrally acting alpha1-adrenoceptor antagonist, has led to large reductions in nightmares and insomnia in small studies of patients with PTSD. Augmentation of SSRIs with olanzapine, an atypical antipsychotic, may be effective for treatment-resistant nightmares and insomnia, although adverse effects can be significant. Additional medications, including zolpidem, buspirone, gabapentin and mirtazapine, have been found to improve sleep in patients with PTSD. Large randomised, placebo-controlled trials are needed to confirm the above findings. In contrast, evidence suggests that benzodiazepines, TCAs and MAOIs are not useful for the treatment of PTSD-related sleep disorders, and their adverse effect profiles make further studies unlikely. Cognitive behavioural interventions for sleep disruption in patients with PTSD include strategies targeting insomnia and imagery rehearsal therapy (IRT) for nightmares. One large randomised controlled trial of group IRT demonstrated significant reductions in nightmares and insomnia. Similarly, uncontrolled studies combining IRT and insomnia strategies have demonstrated good outcomes. Uncontrolled studies of continuous positive airway pressure for SDB in patients with PTSD show that this treatment led to significant decreases in nightmares, insomnia and PTSD symptoms. Controlled studies are needed to confirm these promising findings.

Neuroendocrine Regulation of Sleep Disturbances in PTSD

Studies that have conducted quantitative analysis of the sleep electroencephalogram (EEG) have demonstrated decreased delta sleep in PTSD. Elevations in both hypothalamic (neurohormonal) and extrahypothalamic (neurotransmitter) corticotropin releasing factor (CRF) release is associated with decreased delta sleep activity. We present data from several studies examining the effect of metyrapone administration on the sleep EEG in PTSD and control subjects. Plasma ACTH, cortisol, and 11-deoxycorticol were obtained the morning following polysomnographic sleep recordings before and after metyrapone administration. Delta sleep was measured by period amplitude analysis. The results demonstrate: a) decreased delta sleep in male subjects with PTSD; b) metyrapone administration resulted in an activation of the sleep EEG and a robust decrease in quantitative delta sleep; c) the sleep and endocrine (increase in ACTH) responses to metyrapone were significantly decreased in PTSD in two different study samples; and d) the metyrapone-related disruption to sleep in both samples was predicted by the increase in ACTH measured the following morning. These findings strongly suggest that the delta sleep response to metyrapone is a measure of the brain response to a hypothalamic CRF challenge. The attenuated delta sleep and endocrine response to metyrapone challenge in PTSD is consistent with a model of enhanced negative feedback regulation or downregulation of CRF receptors in an environment of chronically increased CRF activity.

To breathe, perchance to sleep: sleep-disordered breathing and chronic insomnia among trauma survivors

Standard psychiatric classification (DSM-IV-TR) traditionally attributes post-traumatic sleep disturbance to a secondary or symptomatic feature of a primary psychiatric disorder. The DSM-IV-TR paradigm, however, has not been validated with objective sleep assessment technology, incorporated nosological constructs from the field of sleep disorders medicine, or adequately addressed the potential for post-traumatic stress disorder (PTSD) sleep problems to manifest as primary, physical disorders, requiring independent medical assessments and therapies. This paradigm may limit understanding of sleep problems in PTSD by promulgating such terms as "insomnia related to another mental disorder," a.k.a. "psychiatric insomnia." Emerging evidence invites a broader comorbidity perspective, based on recent findings that post-traumatic sleep disturbance frequently manifests with the combination of insomnia and a higher-than-expected prevalence of sleep-disordered breathing (SDB). In this model of complex sleep disturbance, the underlying sleep pathophysiology interacts with PTSD and related psychiatric distress; and this relationship appears very important as demonstrated by improvement in insomnia, nightmares, and post-traumatic stress with successful SDB treatment, independent of psychiatric interventions. Continuous positive airway pressure treatment in PTSD patients with SDB reduced electroencephalographic arousals and sleep fragmentation, which are usually attributed to central nervous system or psychophysiological processes. Related findings and clinical experience suggest that other types of chronic insomnia may also be related to SDB. We hypothesize that an arousal-based mechanism, perhaps initiated by post-traumatic stress and/or chronic insomnia, may promote the development of SDB in a trauma survivor and perhaps other patients with chronic insomnia. We discuss potential neurohormonal pathways and neuroanatomatical sites that may be involved in this proposed interaction between insomnia and SDB.