Table 6.

Correlation of the simplified Japanese version of the Athens Insomnia Scale (AIS‐SJ) with external criterion variables (n = 50 547)

	Psychological distressa . c	PTSDa , d	Mental illnessb	Self‐rated healthb	Experiencing tsunamib	Experiencing NPP incidentb	Bereavementb	Housing damageb	Losing jobb
Total (0–8)	0.60	0.60	0.36	0.51	0.10	0.18	0.17	0.13	0.15
Nocturnal (0–5)	0.50	0.54	0.28	0.46	0.10	0.18	0.16	0.12	0.14
Daytime (0–3)	0.56	0.52	0.37	0.44	0.08	0.14	0.13	0.10	0.13

^aSpearman's correlation coefficients were shown in each cell of psychological distress and PTSD.

^bPolyserial correlation coefficients were shown in each cell of mental illness, self‐rated health, experiencing the tsunami, experiencing the NPP incident, bereavement, housing damage, and losing job. All correlation coefficients were significant (p _s < 0.001). Higher scores for insomnia scales, psychological distress, PTSD and self‐rated health indicate a poorer state in each index.

^cPsychological distress was assessed using the Japanese version of the K6 scale.

^dPTSD was assessed using the Japanese version of the Post‐traumatic Stress Disorder Checklist–Stressor Specific Version (PCL‐S). NPP, nuclear power plant; PTSD, post‐traumatic stress disorder.