QLiS--development of a schizophrenia-specific quality-of-life scale.
BACKGROUND
The aim of the project was to develop an instrument for the assessment of subjective quality of life specific to schizophrenic persons on the basis of patients' views on their own life and on sound psychometric principles.


METHODS
The project applied a six-step multiphase development process with six distinct studies. (1) The elicitation of schizophrenic persons' views on their quality of life was based on open-ended interviews with interviewees from different settings (acute ward inpatients, long-term care patients, community care patients; n = 268). (2) A cross-sectional study with schizophrenic and healthy persons was conducted to quantify the relative importance of the various aspect of quality of life that emerged from the qualitative study (n = 143). (3) We conducted an empirical comparison of response formats with schizophrenic persons (n = 32). (4) A scale construction- and reliability-testing study was performed (n = 203) as well as (5) a test-retest reliability study (n = 49). (6) The final questionnaire (QLiS, quality of life in schizophrenia) was tested in an additional study on convergent and discriminant validity (n = 135).


RESULTS
The QLiS comprises 52 items (plus 2 optional items related to work) in 12 subscales: social contacts, appreciation by others, relationship to family, appraisal of pharmacotherapy, appraisal of psychopathological symptoms, cognitive functioning, abilities to manage daily living, appraisal of accommodation/housing, financial situation, leading a 'normal' life, confidence, general life-satisfaction. An item response format with four response categories was preferred by the schizophrenic persons. The mean values of the subscales clustered around the theoretical mean of the subscales and only minimal ceiling effects were found. The reliability (test-retest-reliability and internal consistency) was with one exception > .70 for all subscales.


CONCLUSIONS
Taking the low numbers of items per subscale into account, the QLiS can be regarded as an accurate assessment instrument of subjective quality of life in schizophrenia with good content validity.
Centre for Psychiatry, Justus-Liebig University, Giessen, Germany.
Michael
M
Franz
Michael
M
Fritz
Bernd
B
Gallhofer
Thorsten
T
Meyer
D000328:Adult; D017668:Age of Onset; D003156:Community Mental Health Services; D003430:Cross-Sectional Studies; D005260:Female; D005858:Germany; D006801:Humans; D007398:Interpersonal Relations; D008297:Male; D008875:Middle Aged; D026684:Personal Autonomy; D010549:Personal Satisfaction; D010865:Pilot Projects; D011567:Psychiatric Department, Hospital; D011594:Psychometrics / Q000379:methods / Q000592:standards*; D036301:Qualitative Research; D011788:Quality of Life; D015203:Reproducibility of Results; D012559:Schizophrenia / Q000503:physiopathology; D012720:Severity of Illness Index; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires