Shift work may cause insomnia and sleepiness in individuals. The present study aimed to exam shift work disorder (SWD), and to investigate their associations with individual characteristics.
A total of 1833 shift workers were assessed using the Pittsburg Sleep Quality Index, Epworth Sleepiness Scale (ESS), Composite Scale of Morningness (CSM), Circadian Type Inventory (CTI), Center for Epidemiologic Studies-Depression Scale (CES-D), Beck Anxiety Inventory (BAI) and other self-compiled socio-demographic questionnaires.
In the current sample, 17.1% shift workers have experienced insomnia symptoms, 20.9% were tested for daytime sleepiness, and 19.9% were categorized as having SWD. Logistics regressions revealed that history of mental disorders (OR = 2.04, 95% CI = 1.30-3.21), chronic physical illness (OR = 1.53, 95% CI = 1.17-1.99), CES-D scores (OR = 1.03, 95% CI = 1.02-1.05), BAI scores (OR = 1.04, 95% CI = 1.03-1.06), languid/vigorous tendencies (OR = 1.06, 95% CI = 1.03-1.10) were positively associated with the onset of SWD, while morningness (OR = 0.97, 95% CI = 0.94-0.99) decreased the odds of SWD onset.
These findings suggested that attention should be drawn to individuals with mental and chronic diseases in when scheduling work shifts. While SWD and its associates should be considered when providing psychological services to shift workers.

Copyright © 2021 Elsevier B.V. All rights reserved.