Imagery rehearsal therapy for chronic nightmares in sexual assault survivors with posttraumatic stress disorder - A randomized controlled trial

Context Chronic nightmares occur frequently in patients with posttraumatic stress disorder (PTSD) but are not usually a primary target of treatment. Objective To determine if treating chronic nightmares with imagery rehearsa l therapy (IRT) reduces the frequency of disturbing dreams, improves sleep quality, and decreases PTSD symptom severity. Design, Setting, and Participants Randomized controlled trial conducted fro m 1995 to 1999 among 168 women in New Mexico; 95% had moderate-to-severe PT SD, 97% had experienced rape or other sexual assault, 77% reported life-thr eatening sexual assault, and 58% reported repeated exposure to sexual abuse in childhood or adolescence. Intervention Participants were randomized to receive treatment (n=88) or to the wait-list control group (n=80). The treatment group received IRT in 3 sessions; controls received no additional intervention, but continued any o ngoing treatment. Main Outcome Measures cores on the Nightmare Frequency Questionnaire (NFQ), Pittsburgh Sleep Quality Index (PSQI), PTSD Symptom Scale (PSS), and Clini cian-Administered PTSD Scale (CAPS) at 3- and 6-month follow-up. Results A total of 114 participants completed follow-up at 3 and/or 6 month s. Comparing baseline to follow-up (n=97-114), treatment significantly redu ced nights per week with nightmares (Co hen d=1.24; P<.001) and number of n ightmares per week (Cohen d=0.85; P<.001) on the NFQ and improved sleep (on the PSQI, Cohen d=0.67; P<.001) and PTSD symptoms (on the PSS, Cohen d=1.0 0; P<.001 and on the CAPS, Cohen d=1.53; P<.001). Control participants show ed small, nonsignificant improvements for the same measures (mean Cohen d=0 .21). In a 3-point analysis (n=66-77), improvements occurred in the treatme nt group at 3-month follow-up (treatment vs control group, Cohen d=1.15 vs 0.07 for nights per week with nightmares; 0.95 vs -0.06 for nightmares per week; 0.77 vs 0.31 on the PSQI, and 1.06 vs 0.31 on the PSS) and were susta ined without further intervention or contact between 3 and 6 months. An int ent-to-treat analysis (n=168) confirmed significant differences between tre atment and control groups for nightmares, sleep, and PTSD (all P<.02) with moderate effect sizes for treatment (mean Cohen d=0.60) and small effect si zes for controls (mean Cohen d=0.14). Posttraumatic stress symptoms decreas ed by at least 1 level of clinical severity in 65% of the treatment group c ompared with symptoms worsening or not changing in 69% of controls (chi (2) (1)=12.80; P<.001). Conclusions Imagery rehearsal therapy is a brief, well-tolerated treatment that appears to decrease chronic nightmares, improve sleep quality, and dec rease PTSD symptom severity.