Impact of hypnotics use on daytime function and factors associated with usage by female shift work nurses

• The rate of hypnotics use among 997 shift work nurses was 10.0%.
• Among 100 hypnotics users, 31 users used two or more different types of hypnotics.
• Multiple hypnotics users showed lower daytime function than a single hypnotic user.
• Higher age, depression, eveningness, and insomnia were associated with hypnotics use.
• Only the existence of shift work disorder (SWD) was significantly associated with multiple hypnotics usage.

ObjectiveWe investigated quality of life (QOL) and work performance of hypnotics users, and explored the factors associated with multiple hypnotics usage in shift work nurses.MethodsWe conducted a questionnaire-based, cross-sectional survey on nurses in university hospitals. We analyzed responses from 1202 nurses; 997 were female shift work nurses (82.9%), including 696 and 281 two- and three-shift workers, respectively.ResultsThe rate of hypnotics use was 10% (6.9% were single hypnotic users and 3.1% were multiple hypnotics users). The rate of insomnia did not differ between the single and multiple hypnotics users. However, multiple hypnotics users showed lower QOL, more severe depressive symptoms, and greater frequencies of work-related errors than those using a single hypnotic. A multiple logistic regression analysis revealed that age ≥27 years, presence of depression, eveningness chronotype, and presence of insomnia symptoms were significantly associated with hypnotics use. On the other hand, only the existence of shift work disorder (SWD) was significantly associated with usage of multiple hypnotics.ConclusionsThe present study suggested that usage of multiple hypnotics is not beneficial for relieving insomnia or for keeping better QOL in shift work nurses. It would be desirable to explore the causal relationship between SWD and multiple hypnotics use in a future longitudinal study.