The self-assessment Global Quality of Life scale: Reliability and construct validity

Area of Science:

• Psychiatry
• Mental Health Research
• Psychometrics

Background:

• Assessing quality of life is crucial for individuals with severe mental illness.
• Existing measures may not fully capture the nuances of perceived well-being in this population.
• The Global Quality of Life Scale (GQL) was developed as part of a broader mental health service documentation platform.

Purpose of the Study:

• To establish the psychometric properties of the Global Quality of Life Scale (GQL).
• To validate the GQL for use with individuals experiencing severe mental illness.
• To assess the reliability and validity of the GQL as a screening instrument.

Main Methods:

• The study involved administering the GQL alongside established instruments such as MANSA, Inventory of Problem and Solutions, and UKU-Side Effect Rating Scale.
• Test-retest reliability of the GQL was evaluated over quarterly intervals for one year.
• Concurrent validity was assessed by comparing GQL scores with specific items from validating measures.

Main Results:

• The Global Quality of Life Scale (GQL) exhibited very satisfactory test-retest reliability at quarterly intervals.
• Concurrent validity was confirmed through significant associations with the "Life as a whole" item of the MANSA.
• Content validity was supported by correlations with multiple validating measures across different contexts and studies.

Conclusions:

• The Global Quality of Life Scale (GQL) possesses acceptable psychometric properties and is a valid instrument for individuals with severe mental illness.
• The GQL is a user-friendly tool suitable for screening perceived global quality of life.
• Findings support the integration of the GQL into routine clinical follow-up for mental health services.