Case 73: Co-Morbidity of Sleep Disorders in Veterans with PTSD: An Integrated Synopsis of 109 Studies (1995-2020)

Co-Morbidity of Sleep Disorders in Veterans with PTSD: An Integrated Synopsis of 109 Studies (1995-2020)

Chris Piotrowski

        Sleep disturbances are a prominent feature of PTSD, quite evident in the veteran population. The scope of published literature on the PTSD-Sleep nexus is rather voluminous; yet reviews on this body of scholarship, from a bibliometric perspective, are rather nonexistent. The current study aims to provide a synthesis of this select literature using a bibliometric content analysis approach. To that end, the dataset was targeted on primary research, i.e., peer-reviewed articles indexed in the database PsycINFO. The search was limited to studies where the main focus was on the combined topics of sleep disorders and PTSD (in veteran populations only), evident from the Abstract of individual articles. This procedure yielded 109 articles spanning 1995-2020. The author reviewed and summarized each study in order to garner the main findings of the investigation. The aggregate findings were then integrated into a summary report, based on the general consensus of the analysis. The main conclusions were: In terms of investigatory focus, the most prominent topics were nightmares, obstructive sleep apnea (OSA), and insomnia; several subject areas exhibited moderate levels of research attention, i.e., sleep quality, daytime sleepiness, TBI, combat or blast exposure, and sleep-related body movements. Furthermore, depression and pain represented 12% of the dataset of articles. Noteworthy, nearly all studies noted the efficacy of Cognitive-Behavioral and Imagery Rehearsal approaches in the treatment of Sleep-PTSD symptomatology. Overall, this body of scholarly literature confirms the poly-morbidity of conditions involving the PTSD-Sleep nexus in veteran populations.

 

Introduction:

        There is a myriad of traumatic events that can prompt stress reactions, such as war zone experiences, accidents, physical assaults, and both natural and man-made disasters (Moore & Penk, 2019; Rodriguez et al. 2017; Sripada et al., 2020; Stoddard et al., 2018; Xenakis, 2014). Thus, military veterans can be subjected to multiple major stress events in their lifetime (Pugh, 2014). Whereas lifetime prevalence rates of posttraumatic stress conditions (hereon, PTSD) range from 6% to 8 % in the general population, veterans and active-duty military personnel report rather high rates (about 20%) of PTSD diagnoses (see Katz, 2016).

        Comprehensive clinical assessment has long confirmed that sleep problems are a key hallmark of PTSD conditions, as well as a common comorbid factor in a myriad of mental health disorders (Dikeos & Georgantopoulos, 2011; Fawcett, 2015). Moreover, copious research studies, with a focus on co-morbidity, have confirmed the link between PTSD and significant sleep dysfunction and diagnosed sleep disorders

        (Brim & Riggs, 2019; Caldwell & Redeker, 2005; Dagan et al., 1991; Harvey et al., 2003; Khazale et al., 2016; Pace-Schott & Bottary, 2018; Piotrowski, 2020). A review of the behavioral science literature indicates that scholarly work on the PTSD-Sleep nexus is an active area of research (Piotrowski, 2020). Indeed, sleep disturbances in the context of post-traumatic reactions (i.e., PTSD) are chief complaints of military veterans, supported by findings of copious research (Babson et al., 2013; Bramoweth & Germain, 2013; Cappuccio et al., 2018; El-Gabalawy et al., 2018; Hermes & Rosenheck, 2014; Jaramillo et al., 2015; Lommen et al., 2016; Moore et al., 2020; Shattuck et al., 2013; Soreca et al., 2019; van Liempt, 2012). In a study on major complaints of 812 veterans entering treatment for PTSD, Rosen et al. (2013) found that sleep disturbances and nightmares were identified as major concerns.

        Yet the extant literature on the (role) impact of sleep disturbances on veteran populations with PTSD symptomatology reflects a broad scope of research endeavors. Due to the fact that this is a burgeoning area of scholarly investigation, it would be informative to provide a concise summary of research studies to date. To that end, the aim of the current project is to identify and synthesize key findings of the extant literature on the PTSD-Sleep disorders link, which may offer directions for future research efforts.

Investigatory Approach:

        Bibliometric approaches, including content analysis, applied to the study of mental health issues have gained credence as an acceptable research methodology (Mogil, 2009; Piotrowski, 2014, 2018, 2019). The current study utilized a content analysis strategy of the extant literature. In order to obtain a pool of pertinent articles, the author conducted a Boolean search of the database PsycINFO. The terms PTSD, “sleep disorders” or sleep, and veterans comprised the online search strategy, where all these keywords needed to be noted in the Abstract of peer-reviewed articles. In addition, several additional studies were identified via a manual review of bibliographies of obtained articles. Based on this search strategy, 109 studies were retained as the dataset for the current analysis.

 

Major Conclusions Based on Review:

Based on the content analysis of 109 journal articles, the following were the most pertinent findings with regard to the literature on the nexus of sleep disorders in veterans with PTSD:

• Nightmares/disturbing dreams and obstructive sleep apnea were the most researched topics
• Sleep quality was a major area of scholarly investigation
• Insomnia, TBI, body movements during sleep, and daytime sleepiness comprised about 30% of the dataset of articles in the analysis
• Combat exposure and „blast exposure‟ was the

focus of 10% of the investigations

• The issues of depression or pain represented 12% of the studies
• REM findings accounted for 5% of the dataset
• With regard to treatment, 9 of 10 studies reported significant improvement with cognitive-behavioral interventions; 4 of 6 studies found positive outcomes using imagery rehearsal therapy (IRT); mind-body approaches proved equivocal

        Several observations are worthy of mention: First, several subject areas received scant attention from researchers, i.e., fatigue, exercise, heart rate variability (HRV), obesity, emotion regulation, and alcohol/drug abuse. Second, at least 10% of the studies in the review reported on negative findings; thus, supporting the position that this clinical area of investigation does not reflect publication bias. However, the issue of the „File-drawer problem‟ could not be ascertained.

As the issues of nightmares, insomnia, and obstructive sleep apnea were the predominant areas of research, Table 1 provides a synopsis of the 57 studies where these subject topics were the main focus of study. (For a full summary of the

109 studies, interested readers may contact the author: cpiotrowski@uwf.edu)

 

Table 1. Studies (n=57; 1995-2020) on the topic of Nightmares, Insomnia, or OSA/CPAP in PsycINFO

Study Reference	Aim of Study	Sample/Measures	Major Findings
Mellman et al. (1995)	Study focused on physiological correlates of symptomatic sleep events in PTSD	131 Vietnam combat veterans; sleep diaries and polysomnography	Subjects with diagnosed PTSD reported recurrent awakenings, disturbing dreams, thrashing body movements during sleep, and panic features upon awakening; these symptoms occurred post-REM stage sleep.
Neylan et al. (1998)	Examined the differential role of combat exposure, PTSD symptoms, co-	Vietnam veterans (n=1,167); archival data from national veterans‟	Frequent nightmares were strongly associated with PTSD, accounted for by war zone exposure; however,

..

	morbid psychiatric/medical disorders, and substance abuse to explain domains of sleep disturbances	database	combat exposure was moderately correlated with insomnia and disrupted sleep; frequency of nightmares was not related to alcohol abuse, medical or psychiatric conditions.
Esposito et al. (1999)	Studied dream content in combat-related PTSD	18 Vietnam combat veterans; developed dream report instrument	50% of the sample‟s target dreams contained threatening features; but the type of dream features varied widely.
Engdahl et al. (2000)	Studied the role of REM sleep in PTSD	30 elderly veterans, exposed to war trauma 3 to 5 decades earlier, diagnosed with PTSD; polysomnography	Perceptions of sleep quality for the PTSD group were a) more negative compared to controls, and b) had higher percentage of REM sleep; This PTSD sample also experienced sleep apnea and sleep movement disorders.
Raskind et al. (2003)	Investigated the efficacy of the drug „Prazosin‟ for sleep disturbances in PTSD conditions	10 Vietnam combat veterans with both PTSD and trauma-related nightmares; Clinician-administered PTSD Scale; 5-month double-blind protocol	Prazosin was effective in reduction of distressing dreams, insomnia, and severity of PTSD symptoms; this drug was well tolerated by the sample.
Harb et al. (2009)	Studied the feasibility (CBT) Imagery Rehearsal for treating insomnia and PTSD nightmares	Iraq War veterans (n=7) in treatment	Imagery Rehearsal showed promising post-effects with regard to nightmares, sleep quality, and PTSD symptomatology.
Lu et al. (2009)	Studied imagery rehearsal therapy (IRT) for PTSD nightmares	15 veterans with PTSD who previously completed trauma-focused PTSD treatment; attended 6 IRT group sessions	No benefits reported immediately post-treatment; however, within 3-6 month follow-up, nightmare frequency and PTSD symptomatology decreased significantly; no effects on sleep quality and depression were found.
Plumb (2010)	Investigated types & severity of sleep disturbances in Iraqi/Afghanistan war personnel	Former military personnel; PTSD Checklist, Pittsburgh Sleep Quality Index, Combat Exposure Scale, Anxiety Screen	Majority of sample reported disturbed sleep (56% as “bad”); delayed sleep onset (41%); nighttime awakenings (59%); nightmares (trauma-related, 30%; not trauma-related, 27%); veterans with greater war exposure had more sleep issues; those with higher education levels and ranks reported fewer sleep concerns.
Picchioni et al. (2010)	Investigated the mediating role sleep dysfunctions between combat stress and PTSD	Data, obtained in 2004, from 576 Army veterans of the Iraq War	Insomnia and nightmare scores had large mediation effects between combat stressors and PTSD; authors claim that sleep disturbances contribute to the development & maintenance of a myriad of mental health symptoms.
Wanner et al. (2010)	Studied multi-component treatment for nightmares in PTSD	2 case studies involving Vietnam veterans	Authors cite that 50%-88% of Vietnam veterans experience chronic Posttraumatic nightmares; both veterans in this study showed moderate reductions in sleep disturbances and well as PTSD

			symptoms over the course of treatment.
Nappi et al. (2010)	Studied the efficacy of IRT therapy (relaxation, psychoeducation, cognitive restructuring) for PTSD nightmares	Veterans diagnosed with PTSD; full-course IRT treatment protocol	Those who completed the full-treatment, had significant reduction in nightmare frequency and intensity, severity of insomnia, and PTSD symptoms.
El-Solh et al. (2010)	Studied adherence to various therapies for Positive Airway Pressure in PTSD cases	142 veterans with PTSD; CPAP nightly usage	58% of these patients, with PTSD, were non-compliant with CPAP protocol use, which increased nightmare frequency.
Cook et al. (2010)	Examined the efficacy of imagery rehearsal for PTSD nightmares	124 Vietnam War veterans with chronic PTSD vs. control group; 6 IR sessions delivered in group format	Pre-post changes were noted for sleep quality and PTSD for both groups, but not for nightmares; Imagery rehearsal in group form proved rather ineffective.
Hurwitz & Khawaja (2010)	This paper extols the benefits of treating obstructive sleep apnea (OSA) in patients with PTSD	„Commentary‟ on earlier research study of 142 veterans wi th OSA (see El-Solh et al., 2010)	Author cautions that CPAP treatment for OSA may exacerbate PTSD symptoms or increase nightmare intensity; Thus OSA-PTSD co- morbidity should be a focus of study.
Van Liempt et al. (2011)	Investigated whether Obstructive sleep apnea (OSA) was associated with higher levels of PTSD severity	20 Dutch veterans with combat-related PTSD diagnoses; Clinician-Administered PTSD Scale	High apnea indices were found in 29% of PTSD cases; PTSD severity was linked to OSA; Nightmare severity was similar in PTSD-OSA patients as compared to PTSD patients without OSA.
Capaldi et al. (2011)	To specify sleep difficulties in returning combat veterans of Iraq War	69 combat veterans at the Walter Reed Army sleep clinic; polysomnography (PSG), sleepiness scales; medical diagnoses were obtained, retrospectively, from medical records	Sleep apnea, excessive awakenings, daytime sleepiness were prominent in this cohort of patients; more frequent arousals from sleep were found for PTSD veterans; PSG data differentiated diagnostic categories.
Gellis& Gehrman (2011)	Examined the effects of cognitive therapy (CBT) for insomnia in longstanding PTSD	8 veterans with chronic insomnia & PTSD (Vietnam, 1st Gulf war); actigraphy, subjective evaluation of sleep patterns	Perhaps due to the short duration of CBT, actigraphy-defined sleep, frequency of nightmares, and PTSD severity were unchanged at post-treatment.
Ulmer et al. (2011)	Studied a multi-component CBT strategy in the treatment for insomnia and nightmares in PTSD conditions	22 veterans diagnosed with PTSD; CBT for insomnia, and Imagery Rehearsal for nightmares; sleep diary	Short term effects were significant, with substantial reductions in PTSD symptoms and insomnia severity; Authors suggest implementing target-specific interventions for distinct sleep disturbances.
Long et al. (2011)	Examined exposure group therapy for nightmares in treatment for PTSD	37 veterans diagnosed with both PTSD and nightmares; 6 group sessions of Imagery Re- scripting and Exposure	Findings indicated that this novel treatment approach reduced PTSD severity and nightmare frequency; Sleep duration was also increased.

..

		Therapy
Wright et al. (2011)	Conducted an evaluation on whether insomnia is an antecedent vs. consequence of PTSD	659 Iraq War combat veterans; Longitudinal design (4 months vs. 1-yr. post-deployment)	Insomnia and psychological symptoms were associated across both time frames; Findings support the role of insomnia in the development of additional co-morbidity.
Wallace et al. (2011)	Compared insomnia characteristics in Iraqi war veterans with PTSD & TBI versus those with PTSD alone	36 veterans in treatment at the Miami VA Post-Deployment clinic; assessed for sleep disorders, pain, depression and quality-of-life‟; underwent polysomnography & kept sleep diaries	Significant co-morbidity for sleep disorders was found for insomnia patients; despite obtaining more sleep, PTSD-TBI veterans experienced more daytime sleepiness.
Holowka et al. (2012)	Examined comorbid diagnostic features of PTSD in veterans	798 Vietnam veterans meeting criteria for „current‟ PTSD and 189 for „lifetime‟ PTSD	Flashbacks, nightmares, and interpersonal detachment had the greatest degree of diagnostic specificity; These findings were consistent with symptomatology of trauma-exposed veterans.
Yesavage et al. (2012)	Studied sleep-disordered breathing (SDB) in veterans with PTSD	105 Vietnam War veterans; polysomnography and cognitive testing data	69% of sample had high apnea index scores; Cognitive assessment profile was not associated to SDB.
Schoenfeld et al. (2012)	Presented a review of prior findings on efficacy of pharmacotherapy and CBT treatments for sleep disturbances in PTSD patients	Review of the literature study	CBT and Imagery rehearsal therapy are as effective as pharmacological treatments (e.g., Prazosin); CBT has targeted insomnia and nightmare complaints in PTSD veterans.
Margolies et al. (2013)	Studied the impact of combined CBT intervention for insomnia and nightmares in PTSD treatment	40 combat Iraq War veterans; 4 sessions of CBT with adjunctive IRT treatment	Patients who participated in combined CBT/IRT reported improved sleep quality, and a reduction in PTSD symptom severity and distressed mood.
Hasler et al. (2013)	Examined psychological and neural correlates of chronotype in PTSD	36 combat-exposed veterans with varying degrees of PTSD; evaluated PET scans, REM sleep, diaries, and polysomnography	Evening-type vets had greater PTSD symptoms, more disturbed sleep, and intense nightmares; Chronotype is linked to neural activity in arousal regulatory regions in vets with PTSD
Pigeon et al. (2013)	Studied the prevalence and severity of PTSD related to nightmares and insomnia over time	80 veterans recruited from VHA primary care facilities; Insomnia Severity Index and PTSD Checklist; 6-mo. post baseline assessment	Insomnia and nightmares were strongly associated with severity for both PTSD and depression; insomnia persisted, over time, with PTSD scores. Authors suggest that addressing insomnia early in treatment may reduce PTSD severity.
Baddeley & Gros (2013)	Evaluated CBT as a pre- treatment protocol to	Case study; veteran with comorbid insomnia and	Significant reductions in insomnia and PTSD were found after the CBTI-

	exposure therapy in PTSD	PTSD; 6 CBTI sessions, followed by 7 sessions of trauma-specific exposure therapy	Exposure therapy protocol; and these results were noted after a 3 month follow-up.
Plumb et al. (2014)	Studied the impact of deployment in the Iraq war on a variety of sleep disturbances related to co-morbid conditions	375 active military and veterans; Pittsburgh Sleep Quality Index, PTSD Checklist-Military version, PHQ-9	45% of the sample reported difficulties in sleep onset, sleep duration, and insomnia; sleep problems were related to combat exposure, increased depression & anxiety scores, and PTSD symptomatology; sleep disturbances tend to have comorbid mental health factors.
Tamanna et al. (2014)	Investigated the effect of CPAP on nightmares in PTSD	69 veterans with both OSA and PTSD; polysomnographic data, Epworth scale	Reduced nightmare frequency after CPAP treatment was best predicted by CPAP compliance; PTSD patients need to be screened clinically for symptoms of OSA.
Germain et al. (2014)	Examined insomnia, sleep quality, depression, and anxiety levels in veterans	40 OEF/OIF/OND combat-exposed veterans; 4-week treatment involving sleep-promoting behaviors; used insomnia and sleep quality indices, PTSD Checklist and Beck inventories	Both interventions (suggestions vs. reading material) showed improvement in insomnia; Apparently, educational self-help strategies can be effective in the treatment of insomnia in veteran populations.
Lang et al. (2014)	Studied the role of insomnia in wounded veterans with PTSD/ pain symptomatology	Retrospective medical records of 137 veterans at a VA Polytrauma clinic	52% of this sample had high prevalence for PTSD, insomnia, and pain; PTSD and pain severity were positively correlated; Authors argue that sleep disturbances affect pain tolerance and promote cognitive deficits; thus, compromising rehabilitation efforts in poly-trauma veterans.
Forbus& Kelly (2015)	Determination of obstructive sleep apnea (OSA) risk in veterans seeking PTSD treatment	264 veterans (26% female)	The rate of OSA risk was nearly 73% for the entire sample; but OSA risk was not correlated with PTSD symptom severity; treatment for OSA could reduce complaints of insomnia.
Ghadami et al. (2015)	Studied both objective and subjective indices of disrupted sleep in veterans	32 veterans with PTSD experiencing insomnia; PSQI and CA-PTSD scale; Actigraphy data	Results indicated that „self-report‟ data is unreliable in these patients; thus, „objective‟ assessment (e.g., actigraphy) is required for valid evaluation protocols.
Gehrman et al. (2015)	Utility of Sleep diaries in sleep disturbances	In a 6-week prospective design, 105 veterans completed sleep diaries	Daytime stressors were associated with increased nightmare frequency; PTSD severity were related with sleep disruption, duration of sleep, and nightmares.
Straus et al.	Sleep dysfunction	45 OEF/OIF/OND	Sleep efficiency was worse for PTSD

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(2015)	variability in military-related PTSD	veterans with PTSD vs. 25 patients with primary insomnia	vs. insomnia group; Results suggest that there is more „variability‟ in sleep problems with combat exposed veterans.
Stocker et al. (2016)	Examined exposure to blast on sleep in combat veterans with PTSD	71 Iraq war veterans with & without PTSD; sleep measures; REM/NREM sleep	PTSD had a main effect on insomnia severity, sleep quality, and disruptive nocturnal behaviors; no significant blast x PTSD interaction on sleep measure was found; authors state that blast exposure is not linked directly to sleep quality, insomnia, and disruptive sleep beyond the effects of PTSD.
Harb et al. (2016)	Studied the role of lucid dreaming in the context of PTSD and recurrent nightmares	33 middle-east combat veterans; 6-sessions of CBT treatment for insomnia	Pre-treatment, these veterans reported high dream awareness and low dream control; Post-treatment (Rehearsal therapy), dream content increased which was related to reduction in nightmare distress.
Khazale et al. (2016)	Examined sleep-related problems in combat-induced PTSD	Veterans with war-zone experience	There is a strong link between PTSD in veterans and sleep disturbances (i.e., insomnia, nightmares, sleep apnea, parasomnias, and movement of extremities during sleep.
El-Solh et al. (2017)	Investigated the therapeutic effects from CPAP duration and PTSD symptomatology	47 combat veterans with OSA and diagnosed PTSD; polysomnography, Epworth Sleepiness Scale, PTSD Checklist-Military version, nightmare scales; over 3-month period	For patients with prolonged CPAP usage, improvement of PTSD symptoms with those with OSA was more pronounced; treatment adherence was linked to reduction of nightmare distress and frequency.
Reist et al. (2017)	Studied whether sleep disturbances impede therapeutic interventions (i.e., benefits) in PTSD treatment	18 combat veterans with diagnosed PTSD; PTSD Checklist	PTSD patients with sleep-disordered breathing had low PTSD Checklist scores, compared to those without sleep disturbances; Findings suggest that the efficacy of exposure therapy for PTSD patients is affected by sleep quality.
Beck et al. (2017)	Efficacy of the Mantram Repetition Program for PTSD-related insomnia	Veterans with PTSD; a mind-body spiritual intervention with CBT features	Results indicated that this veterans sample showed a reduction in insomnia symptoms, as well as PTSD symptomatology.
Mesa et al. (2017)	Studied Cognitive Processing Therapy (CPT) in veterans with obstructive sleep apnea (OSA)	68 OSA veterans in treatment vs. 276 non-OSA veterans; self-reported PTSD symptoms	OSA-positive patients reported greater PTSD severity post-treatment; OSA-positive patients with CPAP therapy reported less PTSD severity vs. non-CPAP; authors conclude that OSA can reduce effectiveness of CPT in veterans with PTSD.
Haynes et al. (2017)	Examined the effect of sleep disorders on cognitive processing therapy (CPT) outcomes	32 veterans; engaged in CPT for combat-related PTSD;	Patients with moderate sleep-disordered breathing responded best to CPT; authors conclude that sleep disorders can be salient factors in

			discussions on who responds to CPT for PTSD conditions.
King et al. (2017)	Explored patterns of sleep complaints with and without PTSD-TBI context	In this longitudinal design, 291 Iraq war veterans; self-report sleep data	Over 18-month period, there was an average of 25% reduction in sleep disturbance; majority of change occurred within the first 6-month period; veterans with TBI-related PTSD reported changes in sleep quality, fatigue, and nightmare frequency.
Scott et al. (2017)	Examined if history of TBI was associated with response to CBT for PTSD-related sleep problems	94 veterans involved in Imagery Rehearsal as part of CBT in treatment for insomnia and recurrent nightmares	Verbal memory functioning was associated with nightmare distress & frequency, and thus, less likely to benefit from CBT; veterans with TBI displayed greater levels of sleep disturbances.
Phelps et al. (2018)	Examined whether posttraumatic nightmares differed in content dependent on sleep-stage	35 veterans vs. current military members; using ambulatory polysomnography	Of 24 reported nightmares, 10 arose during REM sleep and 14 from non-REM stages; the majority of nightmares were associated with respiratory or leg-movement events; author contend that PTSD-associated nightmares point to other concurrent sleep disturbances.
DeViva et al. (2018)	Studied the effects of cognitive-behavioral therapy sessions in treatment for PTSD on insomnia	47 veterans diagnosed with PTSD; Insomnia Severity Index	Significant improvements in sleep onset and sleep efficiency, but no link to total sleep time.
Lee & Gabriele (2018)	Studied Racial differences on the relationship between PTSD and insomnia and BMI in trauma-exposed	Black vs. White veterans	PTSD & insomnia and BMI were related to BMI, but only for the Black sample; thus. PTSD and insomnia may be a central dynamism in weight-related health problems in Black veterans.
Rezaeitalab et al. (2018)	Studied polysomnographic patterns in veterans with obstructive sleep apnea (OSA) in PTSD and non- PTSD conditions	Iranian male veterans; 40 with PTSD vs. 32 without PTSD; BMI and Epworth Sleepiness Scale	OSA in patients with PTSD was associated with insomnia, but not daytime sleepiness; these results were not confirmed for the non-PTSD group.
Gutner et al. (2018)	Focused on treatment preferences of veterans regarding insomnia, PTSD, and depression	622 young adult veterans; sample obtained via Facebook	Key finding indicated that this sample of vets preferred treatment for insomnia compared to PTSD or depression; there was a preference for personal counseling and App-based self-help treatment.
Colvonen et al. (2019)	Studied the proposition of addressing insomnia prior to implementing	12 veterans with insomnia and PTSD in CBT and 2NITE protocols; sleep	Findings showed decrease in PTSD scores, insomnia severity, and a significant increase in Quality-of-Life

	PTSD treatment	diaries, actigraphy data	index scores; also, there was a significant increase in total sleep time; authors argue that CBT and Prolonged-exposure would augment existing PTSD treatment protocols.
Walters et al. (2019)	Impact of „Prolonged Exposure‟ (PT) modality on sleep	Veterans and post-deployment military members; 12 weeks of PT, PT & IRT/CBT combination; Clinician-Administered PTSD Scale	PE did not improve sleep quality, but lessened PTSD symptomatology; IRT/CBT improved insomnia complaints and somewhat lessened nightmare frequency; thus, targeting sleep concerns in PTSD enhances the efficacy of Prolonged Exposure protocols.
Rosen et al. (2019)	Studied the temporal association between insomnia and PTSD severity	1,649 male and female Iraq veterans; over a 2.5 yr. period, interview data, self-report data, and medical records data were obtained	About 75% of the participants with PTSD reported insomnia difficulties; Vets without PTSD experienced fewer sleep; over time, sleep disturbances predicted increased PTSD severity; Also, particularly among male vets with PTSD, high rates of sedative- hypnotic use were noted.
Leng et al. (2019)	Studied the long-term risk (up to 14 yrs.) of sleep disorders after TBI	Over 364,000 treated in the US VA Health Care Administration; data obtained from the National Patient Care Database	TBI veterans had a significant increased risk of developing sleep disorders, particularly insomnia and hypersomnia; this association did not differ by PTSD status over time.
Lopez et al. (2020)	Investigated insomnia and nightmares in veterans, post-intervention for treatment of PTSD & depression	232 veterans undergoing Behavioral Activation & Therapeutic Exposure	Both insomnia and nightmare episodes were reduced.
DeViva et al. (2020)	Examined relationship between daytime PTSD and sleep duration over 2 days	42 post-2001 veterans; PTSD Checklist (3 times per/day)	High levels of PTSD symptoms follow poor sleep the prior night; but, peak PTSD during the day does not impact next-day sleep quality.

 

Conclusion:

        This review found that the scope of research emphasis on the nexus of sleep and PTSD has focused beyond the traditional pathophysiology of sleep disturbances, to include mental health aspects of these comorbid conditions. Moreover, nearly all of the studies in this analysis employed high-level methodologies and cited extensive, salient literature. The investigations on the topic of nightmares, insomnia, and obstructive sleep apnea (OSA) were the predominant research domains in

studies on veterans with PTSD (see Sacre, 2012). In fact, the VA and DOD practice guidelines for management of PTSD emphasize the central role of nightmares in PTSD-related insomnia. Future bibliometric analyses could shed some light on any significant differences between younger versus elderly veterans in coping with PTSD-Sleep dysfunction (Gamaldo et al., 2016), as well as empirical studies on the efficacy of medications for various sleep disorders in veteran populations.

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