Resilience and Readiness through Restorative Sleep

Prior to the wars in Afghanistan and Iraq, suicide was the third leading cause of death in the Armed Forces, following accidents and illnesses.¹ Suicide remained in third place after the beginning of the wars, when war-related deaths and accidents became the leading causes of death, and surpassed the suicide rate of 19.2 per 100,000 in civilians in 2008, before declining again in 2012.^2–4

In parallel, military surveillance reports showed a 19-fold increase in the diagnosis of insomnia between 2000 and 2009.⁵ Surprisingly, a comparable rise in the incidence of the diagnosis of insomnia has not been observed in the Veterans Health Administration (VHA). However, the high rates of hypnotic prescriptions would suggest that this is due to under-diagnosis, rather than a true absence of insomnia in veterans who seek care in VHA clinics.^6,7

Insomnia has been reported to be a reliable risk factor for suicidal ideation, behaviors, and suicide deaths in civilians and military samples.^8–12 However, whether treatment of insomnia can reduce suicidal ideation, behaviors, or deaths has been uncertain. In this issue of SLEEP, Trockel and colleagues¹³ ex plored this question and leveraged data collected from veterans with insomnia who were treated by clinicians enrolled in the VHA dissemination trial for the cognitive behavioral treatment of insomnia (CBT-I). This dissemination trial aimed to increase the number of mental health providers trained to deliver evidence-based cognitive-behavioral treatment of insomnia in VHA clinics.^14–16 In this study, 405 combat- and non-combat veterans between the ages of 22 to 85 years old completed self-report measures of insomnia and depression at baseline and at the completion of CBT-I treatment. Suicidal ideation was measured by extracting one item from a depression scale. The intervention included one session for assessment and up to 5 individual treatment sessions. After adjusting for psychosocial variables, pretreatment to posttreatment improvement in insomnia severity was associated with significant reduction in suicidal ideation. Reduction in insomnia severity was also associated with reduction in the severity of the remaining depressive symptoms, which in turn partially mediated the relationship between the change in insomnia severity and reduction in suicidal ideation. However, the direct relationship between improvement in insomnia and reduction in suicidal ideation remained significant in the adjusted statistical model. Thus, improvement in insomnia directly and indirectly (through reduced depression) reduced suicidal ideation.

While the dissemination trial of Trockel et al. was not designed to test the impact of CBT-I on suicide-related outcomes, this is one of largest archival data analysis studies to show that clinically meaningful improvement in insomnia severity following a brief course of CBT-I can decrease suicidal ideation among military veterans. Other strengths of the study include the use of the Insomnia Severity Index,^17,18 a well-validated self-report measure of insomnia severity, the relative representativeness of the sample, and exploratory analyses to suggest that CBT-I reduces suicidal ideation in both men and women veterans. Important limitations acknowledged by the authors are (1) the absence of a comparison group, which may overestimate the impact of CBT-I on suicidal ideation; (2) the absence of follow-up assessments, needed to estimate the potential durability of the observed effects on suicidal ideation; and (3) the lack of information regarding past or current diagnoses of major depression, posttraumatic stress disorder (PTSD), alcohol/substance use disorders, history of traumatic brain injury or current concussive symptoms, or use of hypnotics or psychotropic medications that often are found in veterans with insomnia. Other study limitations relate to the absence of validated and more comprehensive measures of suicidality and sleep-disordered breathing.

Although insomnia is an established factor of risk for suicide-related and other poor health outcomes,^19–26 this study adds to the extant literature in three main ways. First, Trockel explored the extent to which varying treatment doses, defined as the number of sessions attended, impacted improvement in insomnia and suicidal ideation.¹³ Although session attendance is a distal proxy for adherence to CBT-I recommendations, the authors nevertheless show that fewer sessions yielded greater improvements on the Insomnia Severity Index than longer treatment duration, and slightly greater reduction in suicidal ideation. This finding suggests brief insomnia treatment can rapidly and significantly improve insomnia as well as symptoms of comorbid conditions. This may be especially important in developing stepped-care models that increase access, delivery, acceptability, adherence, and retention in interventions targeting suicidality.^27–30 Second, subgroup analyses revealed a greater reduction in suicidal ideation among women veterans following CBT-I relative to improvement seen in men. Finally, the findings of Trockel support wide-scale effectiveness trials to test the potency of behavioral (or pharmacological) insomnia treatments as means to prevent suicide-related outcomes.

Like others, Trockel highlighted the need for rigorous prospective clinical trials to directly evaluate the impact of insomnia treatments as a strategy for suicide prevention both in civilians and military populations. A search of clinicaltrials.gov (retrieved online, December 20, 2014) revealed that a number of pilot studies and randomized clinical trials aimed at evaluating the short- and long-term benefits of behavioral and/or pharmacological treatments of insomnia on suicide-related outcomes are underway. While many of these trials appear to emphasize the comorbidity between insomnia and depression, it will be critical to include rigorous and clinically accepted measures to capture the contributions of other psychiatric conditions on the relationship between insomnia and suicidality. For service members and veterans, they should include war-related injuries, including PTSD, nightmares, chronic traumatic brain injury, and chronic pain. Similarly, capturing chronic sleep restriction and other conditions associated with non-restorative sleep beyond the diagnosis of insomnia will be important in understanding factors that contribute to heightened suicidality among veterans and service members and that can be mitigated by sleep-focused treatments. More generally, reliable measurements of “sleep fitness” will be essential not only for the optimization of resilience, readiness, and operational performance, but also for devising deployable sleep-informed suicide prevention efforts.

Testing insomnia treatments in individuals at imminent risk for suicide, such as recent attempters, along with repeated follow-ups during windows of heightened risk of re-attempt in this acute population will also be necessary to determine the full potency of insomnia treatments in the management of suicidality.

The combination of clinical trial methodologies with well-validated and innovative molecular, cellular, psychophysiological, neurobiological, and behavioral measures can provide insight into novel pathways to further personalize insomnia-focused suicide prevention and management strategies. For instance, structural and functional alterations in neural circuits implicated in decision making, response inhibition, reward and motivation, affective valence, and self-referential processes have been reported in suicidal patients, as well as in response to acute or chronic sleep disruption.^31–36 Further investigation of the relationship between consolidated healthy sleep and these neural circuits is needed to fully understand the neurobiological underpinnings of the relationship between insomnia and suicide-related outcomes.

Finally, it is noteworthy that insomnia and short sleep duration also affect non-deployed service members.^5,37,38 Thus, insomnia-focused detection, prevention, and treatment strategies may be beneficial in preventing accidents and illnesses, the other primary leading causes of death among service members. Consolidated restorative sleep is not only a matter of public health, it is also a matter of military fitness and readiness,³⁹ and of national security.⁴⁰

CITATION

Germain A. Resilience and readiness through restorative sleep. SLEEP 2015;38(2):173–175.

DISCLOSURE STATEMENT

Dr. Germain has indicated no financial conflicts of interest.