Insomnia is a commonly occurring sleep problem in shift workers. So far, no studies have investigated how insomnia symptoms present differently in shift workers and non-shift workers. The purpose of this study was to compare the network structures and centrality indices of shift and non-shift workers using network analysis and network comparison test. Participants included 1339 hospital employees, where 542 were shift workers and 797 were non-shift workers. Overall, a significant difference between network structures were observed. In particular, daytime dysfunction emerged as a strongly connected symptom in shift workers, as evidenced by strength centrality. Increased use of sleeping medication and decreased habitual sleep efficiency were more strongly associated with increased daytime dysfunction in shift workers. Sleep latency and sleep quality were also more strongly linked in shift workers. These results are in part attributable to differing causes of insomnia in shift and non-shift workers. Furthermore, the results indicate that shift workers are more vulnerable and susceptible to changes in sleep-related indices, such as sleep efficiency and latency. The findings suggest that certain insomnia symptoms are more consequential in shift workers, emphasizing the need for a differentiated approach in treating insomnia according to shift work.
Keywords: Insomnia; Pittsburgh Sleep Quality Index; daytime dysfunction; network analysis; shift work; sleep efficiency; sleep latency.