Longitudinal relationships of insomnia, nightmares, and PTSD severity in recent combat veterans
Introduction
Sleep disturbances have often been considered a hallmark of posttraumatic stress disorder (PTSD) [1], [2] with good reason. Both insomnia and nightmares are independently associated with PTSD and comprise specific symptoms in PTSD diagnostic criteria [3]. Insomnia occurs in 60–90% of PTSD patients and is the most commonly endorsed PTSD symptom; nightmares occur less frequently (~ 50%) [4], [5].
Among the U.S. military service members deployed to combat and among veterans receiving primary care in the Veterans Health Administration (VHA) sleep disturbance is highly prevalent. Recent reports indicate that, during deployment, poor sleep environment, night-time duties, personal life-related stress, and combat-related stress disturbed sleep more than half the nights for 33%, 30%, 11%, and 10% of soldiers, respectively [6]. Sleep disturbance also represents the second most common complaint of recent returning veterans [7]. Finally, among 886 veterans screened in primary care, 88% met risk criteria for at least one sleep disorder, 49% met for more than one sleep disorder, and 24% reported use of sleeping pills or alcohol at bedtime to help with sleep [8].
While nightmares tend to diminish following PTSD interventions, insomnia tends to remain as a common residual problem [9], [10], [11], [12]. Thus, it is conceivable that patients with PTSD have more difficulty engaging in PTSD interventions when sleep disturbances are present, adding to the clinical importance of insomnia and nightmares among such patients.
Unlike the fairly extensive literature used to establish insomnia as a risk factor for depression [13], relatively few investigations examine the longitudinal relationship of sleep disturbance and PTSD. These include observations that pre-existing sleep difficulties predicted the development of PTSD following exposure to Hurricane Andrew [14], that following civilian injuries, PTSD at 1 year was significantly predicted by sleep complaints at 1 month [15], and that the development of PTSD symptoms was associated with fragmented REM sleep during the one month following serious injury [16]. In the only longitudinal study we are aware of that assessed sleep and the clinical course of PTSD, the presence of sleep disturbance reduced remission rates of PTSD from 56% to 34% over a five year follow-up period [17]. No such longitudinal data exists with respect to combat-related PTSD, despite reports that 4% of recent combat veterans seen in VHA care carry diagnoses for both PTSD and a sleep disorder [18] and that insomnia and PTSD are strongly associated in veterans [19].
In the current observational, longitudinal study, we first describe the prevalence of PTSD, insomnia and nightmares in a sample of recent combat veterans and then examine to what extent these conditions persist and whether insomnia and/or nightmares are associated with the clinical course of PTSD. Data was collected as part of a prospective study of recent veterans with PTSD symptoms and hazardous drinking (1I01CX000175) testing mediators and moderators of the association between PTSD symptoms and alcohol consumption, including sleep disturbance. PTSD and hazardous drinking commonly co-occur. In fact, a recent national study of recent combat veterans found that 63% of recent combat veterans with an alcohol use disorder also had PTSD [20]. Further studies conducted in VHA primary care settings found that, among recent Iraq and Afghanistan veterans, 23–27% screened positive for hazardous drinking, 37–39% screened positive for PTSD, and 16% screened positive for both [21], [22].
The current study was carried out in accordance with the Declaration of Helsinki principles and was approved by the Syracuse VA Institutional Review Board; all participants provided written informed consent.
Section snippets
Sample
Participants (N = 80) were predominately male (n = 64, 80%), recent combat veterans with a mean age of 30 years old (SD = 7.7); the sample characteristics are displayed in Table 1.
Veterans were recruited from VHA primary care based on positive screens on the three-item Alcohol Use Disorders Identification Test (AUDIT) Consumption screen [23] or the four item Primary Care PTSD screen (PC-PTSD; [24]), each of which is widely used to screen patients in VHA settings.
Eligibility criteria included:
Insomnia outcomes
At baseline, the mean ISI score for those who completed the instrument (N = 72) was 14.6 (SD = 7.4). Of these, 73.6% met or exceeded the cutoff for diagnostic-level insomnia (ISI ≥ 11). Participants with insomnia, compared to those without insomnia, had higher baseline levels of PTSD severity, depression severity, and alcohol use. Having insomnia, compared to not having insomnia, was also associated with significantly higher severity of PTSD and depression at the six month assessment (see Table 2).
Discussion
In this longitudinal, observational study of recent combat veterans with PTSD, 74% met clinical cutoffs for persistent insomnia and 61% endorsed having at least moderately distressing nightmares. Those with insomnia at baseline had significantly higher levels of both PTSD and depression severity, a difference which remained six months later. In addition, rates of insomnia and insomnia severity were relatively unchanged after six months, despite a decrease in the rates and severity of PTSD and
Disclaimer
The authors' views or opinions do not necessarily represent those of the Department of Veterans Affairs or the United States Government.
Competing interest statement
All authors have completed the Unified Competing Interest form at http://www.icmje.org/coi_disclosure.pdf and declare that in the past three years author Pigeon has had the following relationships unrelated to the manuscript, but that could be perceived to constitute a conflict of interest: manuscript preparation fees from the Academic Press for a chapter entry, one time speaker training fees from Purdue Pharma for the Intermezzo speaker program, a one time consulting fee from Consumer Reports,
Acknowledgments
This research was funded by the Department of Veterans Affairs (VA) Office of Research & Development (1I01CX000175); work on this manuscript was supported in part by the VA Center for Integrated Healthcare in Syracuse, NY and the Center of Excellence for Suicide Prevention in Canandaigua, NY.
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