[3] The QLDS questions centre around a number of needs that were considered crucial in order to suffice a high quality of life.
The high number of items in the questionnaire allows the detection of moderately minor changes in quality of life.
[3] The development of the QLDS coincided with a rising interest on the impact of illness and its treatment on the quality of life of the patient.
McKenna and Hunt constructed the QLDS on the basis of providing a measure for this, as well as attempting to overcome contemporary studies concerning low correlations between patient self-assessment and nurse or therapist evaluations.
[7] The items in the UK English QLDS were derived from statements made in qualitative interviews by 30 depressed or recently recovered patients based in the North West of England and Scotland.
After a refinement process, based on categories of needs proposed by McKenna and Hunt, 426 relevant statements were derived from the interview transcripts.
Interviewees expressed a great degree of approval with the questionnaire, although a few mentioned how the binomial system caused difficulty, as it required them to make complete choices.
Researchers also faced further difficulty due to the contemporarily high rate of illiteracy, as the test could not be self-administrative on as large a scale as anticipated.
As a result, although the data demonstrated both reliability and construct validity, they were unable to place confidence in the Arabic adaptation's equivalence to the other developed versions.
In the UK this was the General Well-Being Index (GWBI) whilst in the Netherlands the Sickness Impact Profile (PS-SIP) acted as a comparison.
The QLDS was concluded by the researchers to be responsive to change in quality of life throughout successful pharmacological depression treatment.
[3] Since its development, the QLDS has been adapted and validated in 17 languages other than UK English,[2] including Norwegian,[5] Spanish, Danish, French, German and Italian.