Nocturnal Olfactory Stimulation for Improvement of Sleep Quality in Patients With Posttraumatic Stress Disorder: A Randomized Exploratory Intervention Trial

Abstract

Posttraumatic stress disorder (PTSD) is characterized by sleep impairment and nightmares. As pleasant odors presented during sleep affect the emotional tone of dreams without inducing arousal, we investigated whether sleep patterns in PTSD can be improved via nocturnal olfactory stimulation. Participants were 40 inpatients with PTSD (n = 35 women; age range: 20–59 years) who completed a randomized, patient‐blind, placebo‐controlled trial. Baseline measurement for 5 consecutive nights was followed by a 5‐night experimental intervention or placebo trial. During the intervention, patients received nocturnal stimulation with a pleasant odor (odor condition) or clean air (placebo condition) via an olfactometer that delivered inspiration‐triggered stimuli in a nasal tube or via an odorized nasal clip. After each night, the patients completed standardized questionnaires that assessed sleep parameters and dream content. Each night, sleep efficiency, sleep onset latency, and wakefulness after sleep onset were monitored with a motion biosensor. Baseline assessment revealed that PTSD severity was associated with poorer sleep outcomes. An interaction effect showed that nocturnal odorization affected dream intensity. Post hoc tests revealed an improvement in the group that used the nasal clip as compared to baseline, d = 0.68. No negative effects were observed after odorization with the nasal clip. Considering the limited sample size, the study indicates that nocturnal olfactory stimulation may serve as a low‐cost concomitant intervention to improve sleep quality in PTSD.

Post-sequelae one year after hospital discharge among older COVID-19 patients: A multi-center prospective cohort study

“…33 Further, the emerging sequelae, including sweating, anxiety, palpitation, edema of lower limbs, smell reduction, and taste change, were all psychological responses and associated with posttraumatic stress disorder (PTSD). [34][35][36] In our results, anxiety was universal in all subjects, no matter the severe or the non-severe. This indicated that the psychological comfort after hospital discharge of COVID-19 should not be neglected.…”

Olfaction-Related Factors Affecting Chemosensory Dream Content in a Sleep Laboratory

“…Early dream researchers used straightforward techniques of odour presentation, such as spraying odorants on the sleeping person’s pillow, to explore whether being exposed to odour can modify sleep mentation and its content [ 27 ]. Current scientific studies, in which simple odour administration techniques have been superseded by sophisticated olfactometry, have corroborated the notion that smells can indeed affect some aspects of sleep mentation [ 16 , 18 , 28 ]. Even so, it is rare for olfactory stimuli to be incorporated into MSEs [ 18 , 19 , 29 ], be it directly, so that individuals report dreams about the stimulus used for exposure, or indirectly, that is, by triggering the appearance of stimulus-related themes.…”

Sleep Management in Posttraumatic Stress Disorder (PTSD): A Systematic Review

“…We included all studies reporting on sleep outcomes but, with few exceptions (Cook, Harb, et al, 2010;Jacobs-Rebhun et al, 2000;Raskind, Peskind, Chow, et al, 2018;Schäfer et al, 2019;Talbot et al, 2014), studies did not report a power calculation for sleep outcomes. In addition, a small proportion of studies addressing sleep reported a post hoc analysis indicating insufficient power to detect differences between treatment arms (Bormann et al, 2018;Cates et al, 2004;El-Solh et al, 2017;Galovski, Harik, et al, 2016;Harb, Cook, et al, 2019;Krakow et al, 2001;Krystal, Pietrzak, et al, 2016;Mack, 2014;Walters et al, 2019;Whitworth et al, 2019).…”

“…The majority of the included studies were conducted in outpatient settings. Only six studies took place in inpatient facilities (Ahmadi et al, 2015;Donner, Schellong, Hähner, Kerstin, et al, 2017;King et al, 2015;Peniston, 1986;Rosenbaum, Sherrington, and Tiedemann, 2015;Schäfer et al, 2019). Three studies combined inpatient and outpatient settings (Bartzokis et al, 2005;Keane et al, 1989;Peniston, 1986); two were administered remotely (Lange, Van de Ven, et al, 2001;; and one took place within the patient's household (Igreja et al, 2004).…”

“…Three studies reported on participants with trauma due to natural or manmade disasters (Meng et al, 2012;Telles et al, 2010;Zang, Hunt, and Cox, 2014). The remainder reported on mixed populations with regard to type of trauma (Ahmadpanah et al, 2014;Becker et al, 2007;Blanaru et al, 2012;Davidson, Rothbaum, et al, 2001;Hamner et al, 2009;Jindani, Turner, and Khalsa, 2015;Lang, Malaktaris, et al, 2019;Lange, Van de Ven, et al, 2001;McCall et al, 2018;McRae et al, 2004;Meltzer-Brody et al, 2000;Ot'alora G et al, 2018;Pollack et al, 2011;Rasmusson et al, 2017;Schnurr and Lunney, 2015;Taylor et al, 2008;Whitworth et al, 2019;Woodward et al, 2017;Zalta et al, 2019) or other/not specified (Connor et al, 2006;Donner, Schellong, Hähner, Kerstin, et al, 2017;Galovski, Harik, et al, 2016;Germain 2006;Gersons et al, 2000;Jacobs-Rebhun et al, 2000;Kim et al, 2013;McHugh et al, 2014;Petrakis et al, 2016;Rosenbaum, Sherrington, and Tiedemann, 2015;Schäfer et al, 2019;Schneier et al, 2015;Talbot et al, 2014;Thunker and Pietrowsky, 2012;Whitworth, 2018).…”