CPAP for Sleep Apnea May Also Improve PTSD in Veterans
Utilizing CPAP is thought to promote consolidation of emotional memory.
Researchers have found that posttraumatic stress disorder (PTSD) symptoms improved in veterans with obstructive sleep apnea (OSA) who were treated with continuous positive airway pressure (CPAP).
Ali A. El-Solh, MD, MPH, from the VA Western New York Healthcare System in Buffalo, New York and the Jacobs School of Medicine and Biomedical Sciences at the University of Buffalo, and colleagues conducted a prospective cohort study that included 47 veterans with PTSD and OSA.1
The following tests were administered at baseline and at 3 months after CPAP therapy: the Epworth Sleepiness Scale (ESS) score, PTSD checklist-Military (PCL-M), Nightmare Distress Questionnaire (NDQ), and the Nightmare Frequency Questionnaire (NFQ). Objective adherence was assessed at 3-month follow-up.
Of the 47 recruited veterans, 40 completed the study: 22 with mild-to-moderate PTSD (PCL-M score 17-59) and 18 with severe-to-very-severe PTSD (PCL-M score 60-85).
The researchers found that:
- Improvements in PTSD correlated with the duration of CPAP usage (r = 0.45; P =.003)
- Veterans with severe-to-very-severe PTSD had a larger improvement in PTSD symptoms (d = 0.65; P =.004) compared with veterans with mild-to-moderate PTSD (d =0.47;
- P =.04)
- The only significant predictor of overall subjective improvement in PTSD symptoms was CPAP usage (OR 10.5; P =.01)
- After 3 months of treatment, significant changes in NDQ and NFQ scores were observed in veterans adherent to CPAP, but correlations with duration of CPAP use were not statistically significant (r = 0.24; P =.13 and r = 0.13; P =.4, respectively)
“The findings indicated that treatment of OSA reduced PTSD severity and diminished frequency of nightmares to a degree that was both reliable and statistically significant,” the investigators wrote.
The researchers noted that prior research speculated that PTSD may be caused in part by an underlying REM sleep dysfunction that is amplified by OSA.2
“The repetitive arousals induced by recurrent hypoxic episodes disrupt emotional reprocessing of traumatic memories that occur normatively in REM sleep, and function to reduce their impact on current cognition,” they wrote.3 “Utilizing CPAP is thought to promote consolidation of emotional memory, which may assist in recovery from traumatic events.”
Summary and Clinical Applicability
In veterans with OSA, improvement in PTSD was more pronounced with prolonged CPAP use: adherence to treatment was associated with fewer nightmares and lessened distress.
Future research of multimodal treatment, including behavioral intervention combined with CPAP, is warranted.
- This study had a limited sample size and consequent lack of statistical power
- This study had no control group, so it is possible that the participants' PTSD symptoms may have improved due to “healthy user” bias: those who are adherent to CPAP may also happen to be more compliant with PTSD treatments
- PTSD diagnosis was not confirmed with a semi-structured interview such as the Clinician-Administered Scale for PTSD
- Self-report scales are vulnerable to response bias
Disclosure: Ali A. El-Solh, MD, MPH, reports receiving grants from the Department of Veterans Affairs (AES) during the study.
- El-Solh AA, Vermont L, Homish GG, Hufel T. The effect of continuous positive airway pressure on post-traumatic stress disorder symptoms in veterans with post-traumatic stress disorder and obstructive sleep apnea: a prospective study [published online February 3, 2017]. Sleep Med. doi:10.1016/j.sleep.2016.12.025
- Mellman TA, Bustamante V, Fins AI, Pigeon WR, Nolan B. REM sleep and the early development of posttraumatic stress disorder. Am J Psychiatry. 2002;159:1696-1701.
- Wagner U, Gais S, Born J. Emotional memory formation is enhanced across sleep intervals with high amounts of rapid eye movement sleep. Learn Mem. 2001;8:112-119.