key: cord-0736596-xuiksaew
authors: Straus, Laura D.; Dolsen, Emily A.; Nishimi, Kristen; Neylan, Thomas C.; O’Donovan, Aoife
title: Worse sleep, worsening post‐traumatic stress disorder (PTSD): Poor sleep quality associated with increases in PTSD symptoms amongst those experiencing high threat of the COVID‐19 pandemic
date: 2022-02-23
journal: J Sleep Res
DOI: 10.1111/jsr.13568
sha: d78d3615ce622c9a3c3f8ad867a5b252e5326a37
doc_id: 736596
cord_uid: xuiksaew

The coronavirus disease 2019 (COVID‐19) pandemic is a global health crisis with the potential to elicit and worsen psychiatric symptoms, particularly post‐traumatic stress disorder (PTSD) symptoms. Identifying modifiable protective factors is critical for preventing and treating PTSD symptoms both during and following the COVID‐19 pandemic. The present study examined associations of self‐reported sleep quality and anticipatory threat appraisals of the pandemic with PTSD symptoms 6 months later in a sample enriched for pre‐pandemic trauma exposure and PTSD. The sample included 590 adults (mean age 38.2 years) who completed a baseline survey in August/September 2020 and follow‐up survey in March/April 2021. The sample was recruited from a pool of participants interested in a prior study about traumatic stress. Participants self‐reported sleep quality and pandemic‐related anticipatory threat appraisals at baseline. PTSD symptoms were assessed at baseline and follow‐up. Baseline sleep quality was associated with PTSD symptoms at follow‐up controlling for baseline PTSD symptoms (B = −2.49, p = 0.001). Perceived anticipatory threat of the pandemic moderated this association such that worse sleep quality was related to more severe PTSD symptoms at follow‐up for participants with higher (B = −4.07, p < 0.001) but not lower (B = −0.43, p = 0.679) anticipatory threat about the COVID‐19 pandemic. These findings suggest that poor sleep quality may enhance vulnerability to later PTSD symptoms during the pandemic, particularly among those individuals who perceived the pandemic as threatening for their future. Treatments that address sleep problems may be beneficial for reducing trauma‐related symptoms during and following the global health crisis.

Community-dwelling adults residing in the United States were recruited from a prior PTSD-focussed study conducted in 2017-2018 (Niles et al., 2020) . Participants were recruited from all 50 States via Craigslist advertisements and Reddit forums related to trauma or post-traumatic stress. Craigslist and Reddit are online communities that allow for recruitment of a broad sample of online users.

Participants (n = 3631) who expressed interest in the [2017] [2018] study were contacted about participating in a follow-up study regarding psychological experiences during the COVID-19 pandemic (Nishimi et al., 2022, under review 

PTSD symptoms were assessed at baseline and follow-up. Past 30day PTSD symptom severity in relation to one's worst trauma was assessed with the 20-item PTSD Checklist-5 (PCL-5; Weathers et al., 2013 ).

Past 30-day sleep quality was assessed at baseline (5-point scale from "very poor" to "very good").

At baseline, participants rated threat of the COVID-19 pandemic to multiple domains of life including work and finances, education and training, social relationships inside and outside the home, and physical and emotional health (5-point scale from "no threat" to "extreme threat") in the next 12 months, as per Niles and O'Donovan (2018) . A mean score of all threat items was created for analyses.

Linear regression was used to test the aims of this study. All analyses controlledforbaselinePTSDsymptoms.First,weexaminedbaseline sleep quality as a predictor of PTSD symptoms at follow-up. Second, | 3 of 5 STRAUS ET AL.

we examined the main effect of baseline sleep quality, the main effect of baseline perceived future threat of the COVID-19 pandemic, and the interaction between baseline sleep quality and perceived future threat of the COVID-19 pandemic on PTSD symptoms at follow-up. Significant interactions were followed-up with simple slopes analyses. The simple slopes were derived from the interaction equation fit and examined the effect of the independent variable at one standard deviation (SD) above and below the mean. An alpha level of p < 0.05 was used for all analyses. All analyses were conducted in R, version 4.0.3.

Among the participants (n = 590), three-quarters identified as women (75.9%), 21.4% identified as men, and 2.7% identified as a gender other than man or woman. The mean (SD) age of the sample was 38.2 (11.0) years. Race and ethnicity were largely representa-tiveoftheUnitedStatesgeneralpopulationwith12.9%identifying

as Black, 10.7% as Asian, 10.2% as Latinx, 62.7% as non-Hispanic White, and 3.6% as other race or more than one race. Two-thirds (66.6%) of the sample had a 4-year college degree or more, and over half (57.3%) of the sample reported full-time employment. Additional demographic and clinical characteristics are reported in Table 1 Thus, poor sleep quality was associated with increased vulnerability to increasing PTSD symptoms over time in the context of high anticipatory threat appraisals. Consistent with our hypotheses, poor sleep quality at baseline predicted more severe PTSD symptoms several months later, even controlling for baseline PTSD symptoms. This finding extends previous literature on the COVID-19 pandemic linking short sleep duration with more severe PTSD when examined cross-sectionally (Tang et al., 2020) . Additionally, our results are consistent with other longitudinal studies identifying disrupted sleep as a risk factor for worsening PTSD symptoms (Neylan et al., 2021) . Sleep disruption leads to impairments in fear processing (Colvonen et al., 2019) , which in turn underlies many symptoms of PTSD. This study adds to the growing body of research suggesting that targeting sleep problems with focussed interventions may improve PTSD symptoms.

Results also supported our hypothesis that poor sleep quality would be most closely associated with worsening of PTSD in those who were experiencing greater anticipatory threat. This finding is in line with evidence that fear reinstatement is associated with more severe PTSD symptoms but only among individuals with poor sleep (Zuj et al., 2018) . Additionally, poor baseline sleep quality has been shown to interfere with trauma-focussed treatment among Veterans with PTSD and traumatic brain injury (Sullan et al., 2021) .

Taken together, these findings suggest that poor sleep may not be a stand-alone risk factor but may act as a vulnerability factor to reduce capacity to cope with other stressors.

There are limitations of the present study that are worth noting.

Results were based on survey data from two time-points, and 302 participants did not provide follow-up data (~34%), raising concern about the generalisability of the findings. Although those lost to follow-up had worse PTSD severity and sleep quality at baseline, they had similar anticipatory threat appraisals. Additionally, we assessed sleep via a self-reported item focussed on global sleep quality. Although there is support for the use of a single-item measures of sleep quality (Snyder et al., 2018) , future studies should include fuller assessments of sleep quality based on subjective and objective data, which will provide more information about which aspects of disrupted sleep are the most salient.Finally,thissamplewasrecruitedfromanunknownpopulation of Craigslist and Reddit users, which limits generalisability. The participants in this study were also more likely to be exposed to traumatic events than the general population. These findings may not generalise beyond individuals with a history of trauma exposure.

In summary, we found poor sleep quality was associated with worsening PTSD symptoms, but only among those individuals who perceived the pandemic to be especially threatening. Studies such as this one provide the opportunity to inform interventions to reduce or prevent PTSD, which is especially important given the large potential for post-traumatic sequelae in the aftermath of the COVID-19 pandemic.

F I G U R E 1 Simpleslopesofthe interaction between baseline sleep quality and baseline perceived anticipatory threat of the coronavirus disease 2019 (COVID-19) pandemic with post-traumatic stress disorder (PTSD) symptoms at follow-up. The grey shading denotes the standard error of the simple slopes

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