We chose the "Mental Health Inventory" in the 5 items version because it is a simple and quick instrument. It is a good instrument for the early diagnosis of people with psychiatric problems and a good measure of the population's mental health. It was designed to evaluate anxiety, depression, emotional control and emotional stability.
The formulated questions were:
In the last 4 weeks how often...?
- (i5a) Were you very nervous.
- (i5b) Did you feel so low on moral that no one could cheer you up.
- (i5c) Did you feel calm and very relaxed.
- (i5d) Did you feel discouraged and sad.
- (i5e) Did you feel happy.
The answer categories were always the same: always (1) almost always (2) a lot (3) sometimes (4) from time to time (5) never (6).

The index was calculated as follows:
MI = 100-(((7- i5a)+ (7- i5b) + i5c + (7- i5d) + i5e)-5)*4, The range of values being from 0 to 100. Higher values indicate better mental health.