Psychological well-being was assessed on the basis of the General Health Questionnaire (GHQ):
01 Have you been able to concentrate on whatever you’re doing?
02 Have you lost much sleep over worry?
03 Have you felt that you are playing a useful part in things?
04 Have you felt capable of making decisions about things?
05 Have you felt constantly under strain?
06 Have you felt you couldn’t overcome your difficulties?
07 Have you been able to enjoy your normal day-to-day activities?
08 Have you been able to face up to your problems?
09 Have you been feeling unhappy or depressed?
10 Have you been losing confidence in yourself?
11 Have you been thinking of yourself as a worthless person?
12 Have you been feeling reasonably happy, all things considered?
Answer options 01:
1. Better than usual/2. Same as usual / 3. Less than usual/ 4. Much less than usual
Answer options 04, 08:
1. More so than usual/2.Same as usual/3.Less so than usual/4.Much less capable/able
Answer options 02, 05, 06, 09, 10 and 11:
1. Not at all/2. No more than usual/ 3. Rather more than usual/ 4. Much more than usual
Answer options 03:
1. More so than usual/2. Same as usual/ 3. Less useful than usual/4. Much less useful
Answer options 07:
1. More so than usual/2. Same as usual/3. Less so than usual/4. Much less than usual
Answer options 12:
1. More so than usual/2. About same as usual/3. Less so than usual/4. Much less so than usual
From questions 01 to 12, the first two answer options (1&2) were converted to 0 and the last two (3&4) to 1. The sum of these 12 items gives a global score of 0 to 12. A higher score indicates a greater likelihood of psychological complaints. The score was then split into [0-1] and [2-12]. A score of 2 or higher indicates recent psychological problems.