Hello Emmanuel,

These papers mark the writing of the instrument; you could try contacting the authors on ResearchGate: 

Sartorius, N. (1993). A WHO method for the assessment of health-related quality of life (WHOQOL). In Quality of life assessment: Key issues in the 1990s (pp. 201-207). Springer Netherlands.

https://www.researchgate.net/publication/284589968

This is the author's ResearchGate page:

https://www.researchgate.net/profile/Norman_Sartorius

WHOQoL Group. (1993). Study protocol for the World Health Organization project to develop a Quality of Life assessment instrument (WHOQOL). Quality of life Research, 2(2), 153-159.

https://www.researchgate.net/profile/Norman_Sartorius/publication/224904023

Whoqol Group. (1995). The World Health Organization quality of life assessment (WHOQOL): position paper from the World Health Organization. Social science & medicine, 41(10), 1403-1409.

https://www.researchgate.net/publication/224904031

If you don't get any help, you could try contacting Aislinne Freeman on Researchgate, who suggested it for this question in 2015; she might have it or know where to find it:

https://www.researchgate.net/post/Which_psychometric_tools_can_be_used_to_measure_effectiveness_of_counseling_services/1

Very best wishes with this,

Mary

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Article Study protocol for the World Health Organization project to ...

Article The World Health Organization Quality of Life Assessment (WH...