Table 1 Anchoring vignettes for sleep and energy in the Japanese World Health Survey

For each of the following situations, to what degree do you think that each person experienced sleep-related problems such as trouble falling asleep, waking up several times during the night or waking up too early in the morning during the last 30 days? Please mark as 1, None; 2, Mild; 3, Moderate; 4, Severe; 5, Extreme/cannot.

Vignette 1: It takes Mr./Ms. Aikawa less than five minutes from the time he/she gets into his/her bed until he/she falls asleep. He/she sleeps soundly and when he/she wakes up in the morning he/she feels that he/she has had a good night's sleep and is full of energy throughout the day.

Vignette 2: Mr./Ms. Ohyama has no difficulty falling asleep and does not wake up during the night but has a hard time getting up every morning. He/she uses an alarm clock but if he/she turns it off, he/she will fall back asleep. He/she is late four out of five days [a week] for work and feels drowsy all morning.

Vignette 3: Mr./Ms. Shindoh finds it easy to fall asleep, but twice a week he/she wakes up during the night and cannot sleep until morning. Recently, he/she is always exhausted at work and has difficulties concentrating on his/her job.

Vignette 4: Mr./Ms. Ohkawa generally wakes up every hour during the night. When he/she wakes up during the night, it usually takes him/her about 15 min to fall back to sleep. He/she does not feel as though he has had a good night’s sleep and feels listless and tired the whole day.

Vignette 5: It takes Mr./Ms. Ichise about two hours [starting] from the moment he/she gets into his/her bed to fall asleep. When he/she wakes up during the night he/she feels agitated and its takes him/her more than one hour to go back to sleep. Three or four times a week, he/she wakes up during the night and cannot sleep again until the morning. He/she is tired every day and all day long and misses work several times a week. He/she cannot play sports or participate in social activities.