Sleep disturbances in posttraumatic stress disorder

Sleep disturbances are common in posttraumatic stress disorder (PTSD), and often persist following PTSD treatment (e.g., Zayfert & Deviva, 2004). However, it is unclear why sleep disturbances are residual, and there are also concerns that poor sleep may interfere with PTSD treatment. Furthermore, it has not been directly investigated whether factors known to maintain insomnia may also contribute to sleep disturbances in PTSD. This thesis presents five studies, designed to investigate five key research questions: 1) Does Cognitive Therapy for PTSD improve sleep disturbances? 2) Do sleep disturbances interfere with the efficacy of psychotherapy for PTSD? 3) How might sleep improvements occur with PTSD therapy? 4) Do factors known to perpetuate insomnia also contribute to sleep problems in PTSD? 5) What may account for persistent sleep problems after otherwise effective PTSD therapy? Study 1 showed that sleep improved more with trauma-focused compared to non-trauma-focused psychotherapy. Updating and reprocessing the trauma memory promoted sleep duration improvements, and sleep improvements were associated with improvements in nightmares and hyperarousal. Pre-treatment sleep did not predict PTSD treatment outcome. Insomnia was residual for over a third of patients after treatment. Study 2 found that sleep improved with CT-PTSD in routine clinical care, but remained residual for nearly half of patients. Further, the results showed that modification of trauma appraisals and reduction in the flashback-quality of intrusions predicted improvements in sleep duration during CT-PTSD. Study 3 presented the development of a new scale to measure pre-sleep cognitive activity in PTSD. Pre-sleep cognitive activity was associated with disturbed sleep in PTSD. The PTSD group reported pre-sleep cognitions with content similar to those with insomnia, but also cognitions that are specific to PTSD. Study 4 showed that pre-sleep cognitive activity mediated the relationship between PTSD symptoms and disturbed sleep. People with PTSD had higher physiological arousal, and more pre-sleep cognitive activity, which was associated with worse subjective sleep. Finally, Study 5, showed that subjective and objective sleep was improved with CT-PTSD, but sleep problems remained residual for half of patients. Residual sleep problems were associated with sub-clinical PTSD and depression symptoms, pre-sleep cognitive activity and physiological arousal. In sum, theses studies showed that sleep improves but remains a residual problem after PTSD therapy. Processing and updating trauma memories, modifying trauma appraisals and reducing re-experiencing symptoms may promote sleep improvements in PTSD therapy. Pre-sleep cognitive activity contributed to disturbed sleep in PTSD, and was associated with residual sleep problems. The results have implications for understanding sleep problems in PTSD and after PTSD treatment, and may have clinical relevance for the treatment of sleep problems in PTSD therapy.