Later sleep schedule and depressive symptoms are associated with usage of multiple kinds of hypnotics

Objective Usage of high doses of hypnotics possibly causes various adverse events. However, the risk factors of using multiple kinds of hypnotics have been inconclusive. To clarify this, we conducted a web-based cross-sectional questionnaire survey on the Japanese adult population. Methods A cross-sectional Internet-linked survey was conducted on 10,016 individuals and 1030 participants (10.3%) having subjective insomnia proceeded to subsequent analyses. The analyzed subjects were categorized into non-users of hypnotics (n = 833; 80.9%), users of a single kind of hypnotic (n = 96; 9.3%), and users of multiple kinds of hypnotics (n = 101; 9.8%). The descriptive variables including demographic data, scores of Center for Epidemiological Studies Depression Scale (CES-D), Short Form-8 Health-Related Quality of Life [QOL (SF-8)], Pittsburgh Sleep Quality Index (PSQI), and other parameters were compared among the groups. Results The users of multiple kinds of hypnotics had the highest mean score of CES-D, the lowest mental component summary of QOL (SF-8), and the latest sleep schedule among the three groups (p < 0.001). Logistic regression analyses revealed that sex (female: OR = 2.38; p < 0.001) and age (≥43 years old: OR = 2.61; p < 0.001) were independently associated with use of a single kind of hypnotic, while later sleep schedule (midpoint of sleep ≥5:30 a.m.: OR = 2.26; p < 0.001) and higher CES-D score (≥16 points: OR = 2.41; p < 0.001) were independently associated with use of multiple kinds of hypnotics. Conclusions Characteristics of users of multiple kinds of hypnotics were different from those of users of a single kind of hypnotic.