Development and Validity of the Japanese Version of the Pre-Sleep Arousal Scale.

Hyperarousal, defined as increased levels of cortical activity and cognitive-emotional reactivity induced by stress, is suggested to be a key factor in insomnia. In particularly, pre-sleep arousal constitutes one of the major features of insomnia. The Pre-Sleep Arousal Scale is the best-known measure used to evaluate pre-sleep arousal. However, a well-validated Japanese version of the scale (PSAS-J) has not yet been established. The aim of this research was to develop and validate such a scale. A cross-sectional questionnaire-based study was conducted via the internet. In total, 237 of 300 participants (mean age 43.28 ± 11.19 years) completely responded to the questionnaires as followed: the PSAS-J, the Insomnia Severity Index, Ford Insomnia Response to Stress Test, and Dysfunctional Beliefs and Attitudes about Sleep Scale. In addition, the participants were divided into two groups: insomniacs and normal sleepers. As a result, the PSAS-J had a two-factor structure similar to that of the original version, i.e., somatic and cognitive arousal subscales. The internal consistency (α = 0.85 to 0.90) and test-retest reliability (r = 0.67 to 0.78) were high. Correlations between the PSAS-J and the above-mentioned scales ranged from 0.35 to 0.53. Discriminant validity showed that the PSAS-J was distinct from the Ford Insomnia Response to Stress Test and Dysfunctional Beliefs and Attitudes about Sleep Scale. The PSAS-J scores were significantly higher in insomniacs than in normal sleepers. Our results suggest that the PSAS-J has high reliability and validity and that this scale is adequate for assessing pre-sleep arousal.