Cognitive Behavioral Therapy for Insomnia Reduces Fear of Sleep in Individuals With Posttraumatic Stress Disorder

Abstract

Study objectives: Our study aims were to examine (1) the association between fear of sleep and posttraumatic stress disorder (PTSD) symptoms, (2) the association between fear of sleep and subjective and objective insomnia symptoms and disruptive behaviors during sleep, and (3) whether fear of sleep decreases following cognitive behavioral therapy for insomnia (CBT-I).

Methods: Forty-five adults with PTSD and insomnia participated in the study. Fear of sleep was assessed using the Fear of Sleep Inventory; PTSD symptoms were assessed using the Clinician Administered PTSD Scale; and sleep disturbance symptoms were assessed using the Insomnia Severity Index, polysomnography, sleep diaries, and the Pittsburgh Sleep Quality Index Addendum for PTSD. Participants were randomly assigned to 8 weeks of CBT-I (n = 29) or a waitlist control condition (n = 16).

Results: Greater fear of sleep was associated with greater PTSD symptom severity, greater nightmare frequency, and greater hypervigilance intensity. Greater fear of sleep was associated with decreased wake after sleep onset (WASO), reduced total sleep time, and greater disruptive nocturnal behaviors. Following CBT-I, there was a significant reduction in fear of sleep compared to the waitlist condition. These improvements persisted 6 months later.

Conclusions: Fear of sleep was related to sleep disturbances specific to trauma rather than "classic" insomnia symptoms. Unexpectedly, greater fear of sleep was associated with reduced WASO. These results may be related to having a truncated sleep period and thus more consolidated sleep. Fear of sleep deceased following CBT-I despite not being a permissible target for this research protocol and not being related to insomnia symptoms.

Clinical trial registration: Registry: CinicalTrials.gov; Name: Treating People with Post-traumatic Stress Disorder with Cognitive Behavioral Therapy for Insomnia; Identifier: NCT00881647; URL: https://ichgcp.net/clinical-trials-registry/NCT00881647.

Keywords: PTSD; cognitive behavioral therapy; fear of sleep; insomnia; posttraumatic stress disorder; sleep disturbance.

© 2018 American Academy of Sleep Medicine.

Figures

Figure 1. Association between fear of sleep and PTSD symptoms.

CAPS total score: r = .40, P < .01, 95% CI (0.12 to 0.62). CAPS hypervigilance intensity: r = .30, P = .04, 95% CI (0.01 to 0.55). CAPS nightmare frequency: r = .34, P = .02, 95% CI (0.05 to 0.56). CAPS = Clinician Administered PTSD Scale for DSM-IV, CI = confidence interval, PTSD = posttraumatic stress disorder.

Figure 2. Association between fear of sleep and objective and subjective measures of sleep disturbance.

WASO (sleep diaries): r = −.43, P < .01, 95% CI (-0.64 to -0.15). TST (PSG): r = −.30, P = .05, 95% CI (-0.55 to -0.01). PSQI-A: r = .42, P < .01, 95% CI (0.12 to 0.62). CI = confidence interval, PSG = polysomnography, PSQI-A = Pittsburgh Sleep Quality Index, Addendum for PTSD, TST = total sleep time, WASO = wake after sleep onset.

Figure 3. Change in fear of sleep following insomnia treatment.

CBT-I: pretreatment FoSI = 28.43 ± 15.45; posttreatment FoSI = 14.31 ± 15.26; 6-month FoSI = 13.17 ± 16.61; pre to post t28 = 6.26, P < .01, Cohen d = 1.16; pre to 6-month follow-up t22 = 5.95, P < .01, Cohen d = 1.20. Waitlist: pretreatment FoSI = 21.43 ± 16.57; posttreatment FoSI = 19.31 ± 14.67; pre to post t15 = 0.79, P = NS, Cohen d = 0.20. CBT-I = cognitive behavioral therapy for insomnia, FoSI = Fear of Sleep Inventory, NS = nonsignificant.

Figure 4. Reduction in fear of sleep predicted by treatment condition by reduction in PTSD symptoms interactions.

Reduction in CAPS total score: CBT-I: r = .57, P < .01, 95% CI (0.24 to 0.78); waitlist: r = −.14, P = NS. Reduction in hypervigilance intensity: CBT-I: r = .43, P = .02, 95% CI (0.06 to 0.67); waitlist: r = −.45, P = NS. CAPS = Clinician Administered PTSD Scale for DSM-IV, CBT-I = cognitive behavioral therapy for insomnia, CI = confidence interval, NS = nonsignificant, PTSD = posttraumatic stress disorder.