Variable | Cohort questionnaire item | Response categories | Categories in present study | |
---|---|---|---|---|
Yes | No | |||
Current stress | Stress means a situation when a person feels tense, restless, nervous, or anxious or is unable to sleep at night because his/her mind is troubled all the time. Are you currently experiencing this kind of stress? | a = not at all, b = just a little, c = to some extent, d = quite a lot, e = very much | d–e | a–c |
Sleep disturbances | How often have you had problems with your sleep these past 30 days (e.g., difficulties falling asleep, repeated awakenings, waking up too early)? | a = never, b = a few times per month, c = several times per week, and d = every day | c–d | a–b |
Symptoms of depression one item two items | During the past month, have you often been bothered by: (a) little interest or pleasure in doing things? (b) feeling down, depressed, or hopeless? | Yes or No | One item:(a) Yes or(b) YesTwo items:(a) Yes and(b) Yes | One item:(a) No and(b) NoTwo items:(a) No and(b) No |
Reduced performance | Have the following complaints influenced your performance at work or in studies over the past 14 days? (a) stress/depressed mood? (b) tiredness | a = No, b = Yes, negligibly, c = Yes, a little, and d = Yes, quite a lot | (a) d or(b) d | (a) a–c and(b) a–c |