The incidence and clinical significance of nightmares is difficult to estimate. The Nightmare Disorder Index (NDI) is a validated measure to evaluate nightmare disorder. However, there is no measure to differentiate trauma-related nightmares compared to TSD, a unique REM parasomnia. TSD is a novel parasomnia presenting with trauma related nightmares (TRN), disruptive nocturnal behaviors, and autonomic surges.

All initial sleep referrals completed intake questionnaires including the NDI, Epworth Sleepiness Scale (ESS), and Insomnia Severity Index (ISI). Patients who endorsed at least weekly nightmares related to trauma, with vocalizations or disruptive nocturnal behaviors, and autonomic surges additionally received a structured clinical interview focusing on thematic content of dreams, dream enactment behavior, and symptoms of autonomic hyperactivity.

102 new patients completed the NDI and 56.9% (58) met criteria for probable ND. Of the 58 patients with probable ND, 13.8% (8) had symptoms consistent with TSD (7.8% of new referrals). Compared to ND patients, TSD patients were more likely to have a higher ISI (24.0 ± 3.0 vs. 18.6 ± 5.6) (p=0.023) and total NDI score (15.8 ± 3.5 vs. 10.0 ± 3.7) (p<0.001), but not ESS (p=0.158). Structured interview revealed all TSD patients had significant daytime distress or impairment. The nature of trauma was combat for 3 individuals, physical assault for 1, and sexual assault for 4. For DNB, 87.5% of patients endorsed vocalization (moaning, screaming, or yelling), 87.5% endorsed movements (tossing, turning, or thrashing), and 37.5% endorsed combative behaviors.

This study reports a high incidence of probable ND among military sleep medicine patients and may be generalizable to civilian populations. TSD appears to be a clinically distinct, more severe parasomnia compared to ND.