To our knowledge, this is the first study targeting chronic sleep disturbances in military veterans that directly compares the effects of a sleep-targeted cognitive-behavioral treatment versus prazosin and placebo condition for controlling for the non-specific effects of treatment. The results suggest that both BSI and prazosin are more effective than placebo for self-reported and clinician-rated global clinical improvements, and reductions in prospective self-reported and diary-based measures of sleep continuity and nightmare frequency. Although subjective sleep improvements tended to be greater in veterans who were randomized to BSI or prazosin, self-report measures of sleep quality and severity of nocturnal sleep disturbances were improved in all three treatment groups over time. Both active treatments were associated with greater rates of treatment response than the placebo condition, but did not differ from one another. Findings from this study replicate previous findings (e.g., 12
) showing that prazosin and behavioral interventions targeting sleep complaints in trauma-exposed samples are associated with clinically meaningful improvements in sleep complaints. However, prazosin was not associated with reductions in nightmares as previously reported (12
). This may be attributable to the inclusion of veterans with low nightmare frequency, the use of prospective sleep and dream diaries, or the inclusion of veterans who endorsed subsyndromal symptoms of PTSD (42% of the sample). Improvements in daytime symptoms were substantial in all three treatment conditions, but did not statistically differ on the clinician-administered and self-report measures of PTSD, depression, anxiety, and disability. The latter contrasts with previous studies that showed significant improvements in daytime symptoms of PTSD, depression, and anxiety following sleep treatment (12
). Marked improvements in daytime symptoms levels may be more easily detectable in patients with more severe psychiatric symptoms, compared to mild to moderate pre-treatment symptom levels observed in the current sample. Generally mild improvements across symptom domains may have resulted from introducing daily (e.g., medication intake, sleep diaries) and weekly (in-person or telephone visits) routines in veterans’ lives throughout the study.
Treatment response rates as defined by subjective insomnia and sleep quality measures were significantly higher in the two active treatment groups, while the CGI-defined treatment response rates only showed a trend for differences among the three groups. This divergence may be attributable to the small sample size, and to the use of sleep-focused measures with greater sensitivity for measuring nightmare frequency, insomnia severity, and sleep quality compared to a global rating scale. Similarly, diary-based and self-report sleep measures indicated modest but significant improvements in sleep and dreaming quality in the BSI group relative to prazosin and placebo. PSG measures did not differ pre- or post-treatment for any of the three groups. The latter suggests that PSG may not be the method of choice to study the mechanisms of effective sleep-focused treatments. Instead, sleep neuroimaging methods may be necessary to capture neurobiological changes that may underlie sleep disturbances and sleep treatment responses.
Interestingly, three treatment groups did not differ at the four-month follow-up assessment. In those who received the active treatments, improvements were maintained over time. The naturalistic design of the follow-up study limits possible extrapolations regarding the factors that may have contributed to sleep improvements over time in all three treatment groups, especially because veterans randomized to placebo were strongly encouraged to seek sleep-specific treatments. More frequent symptom monitoring over time will be necessary in future studies to clarify the course of sleep and daytime symptoms in military veterans, and the relationships between nighttime and daytime functioning.
Although the comparison of two active treatments for sleep disturbances in a group of US military veterans is unique, the present study has some limitations. First, with the exclusion of nearly 65% veterans who were initially screened (n = 1531), the 50 veterans who initiated treatment may not represent all military veterans who endorse clinically significant sleep complaints. Second, the specific medication exclusions were intended to optimize safety and minimize adverse side effects to a possible randomization to prazosin. As a result of these criteria, the test of the effects of BSI was limited to veterans who were also eligible to complete an 8-week course of prazosin. In typical clinical settings, BSI may provide an alternative treatment option for veterans who cannot use prazosin or who do not respond to pharmacological sleep treatments. Further evaluation of the broader effectiveness of prazosin and BSI is needed in a more inclusive sample. Third, the absence of an inactive therapy-placebo control group against the BSI condition also limits the study interpretation. Although participants randomized to the placebo condition received informational brochures from the American Academy of Sleep Medicine on healthy sleep and insomnia (which can be considered a non-pharmacological treatment as usual for sleep disturbances), this condition did not account for the length of time spent face-to-face with an experienced BSI interventionist. Our study design did not fully account for the length of time spent face-to-face with the experienced BSI therapist, and the selected statistical approach may have biased the findings toward BSI. Replication in larger and more heterogeneous samples is necessary to ascertain the robustness of the observed effects. The absence of more frequent, weekly independent clinical ratings of improvements also constitutes one of the limitations of the present study. Finally, testing the impacts of combining BSI and prazosin relative to the effects of either treatment alone may provide a novel approach to effective reduce otherwise treatment resistant chronic sleep disturbances in military veterans.
In summary, sleep complaints are highly prevalent and chronic in military veterans, and have been associated with poor psychiatric and physical outcomes. The present findings suggest that behavioral interventions targeting sleep disturbances offer modestly greater benefits compared to prazosin, and that both BSI and prazosin constitute viable options for the treatment of chronic sleep complaints in those with PTSD symptoms. Further comparative effectiveness research, as well as partnerships with community-based health providers who serve veterans, are also need to enhance the availability of resources to address their sleep disturbances.