Comorbidity of Nightmares in U.S. Military Personnel With Insomnia, Obstructive Sleep Apnea, or Co-Morbid Insomnia and Obstructive Sleep Apnea.

Introduction: Insomnia and obstructive sleep apnea (OSA) are the most prevalent sleep disorders in military personnel. People with both sleep problems (co-morbid insomnia and sleep apnea [COMISA]) experience higher rates of medical and psychiatric comorbidities. Few studies have examined the comorbidity of nightmares among those with insomnia, OSA, or COMISA. This secondary data analysis of data collected in a large sample of military men and women seeking treatment for sleep disturbances aimed to examine the occurrence and impact of nightmares in military personnel with insomnia, OSA, and COMISA.

Materials and Methods: Data collected from a convenience sample of 372 active-duty U.S. military personnel purposefully recruited following a diagnosis based on a clinical evaluation and in-lab video-polysomnography (118 with insomnia, 118 with OSA, 136 with COMISA) were analyzed. The Nightmare Disorder Index (NDI) was used to measure clinically significant nightmares. Self-reported symptoms of insomnia, excessive daytime sleepiness, sleep-related impairment, anxiety, depression, and posttraumatic stress disorder (PTSD) were also analyzed. Chi-squared tests and 2-way analyses of variance were used to address the study aims. This study is a secondary analysis of data collected in the conduct of a prospective observational study originally approved and overseen by the 59th Medical Wing Institutional Review Board, and the U.S. Army Medical Research and Development Command Human Research Protection Office monitored the regulatory approvals.

Results: Nightmares were significantly more likely in those with insomnia (35.6%; n = 42/118) or COMISA (38.2%; n = 52/136) than in those with OSA (14.4%; n = 17/118; both Ps < .001). Although there was not a significant interaction between group and nightmares, planned post hoc analyses found nightmares were associated with worse PTSD symptoms in the insomnia group; anxiety, depression, and insomnia symptoms in the OSA group; and insomnia, sleep-related impairment, anxiety, depression, and PTSD symptoms in the COMISA group.

Conclusions: Nightmares are associated with increased sleep and mental health symptoms among military personnel with OSA, insomnia, and COMISA. Those with COMISA and nightmares (named COMISA-MARES) exhibited the worst symptoms.