Nevertheless, some studies, including the 2004 Belgian Health Survey discussed above, throw some light on this problem in so far as they focus on measur
ing notions such as psychological illbeing (Book II of the Health Interview Survey – Belgium 2004, pp 204-209): “The psychological well-being assessed in the 2004 Belgian Health Survey is measured by means of an instrument (GHQ-12, General Health Quest
ionnaire) that uses scores ranging from 0 to 12. A higher score indicates a higher probability
...[+++]/severity of psychological ill-being.