Background: “Quality of life” has become a main focus of interest in medicine. The Pictorial Thai Quality of Life (PTQL) was developed in order to measure the Thai mental illness both in a clinical setting and community.
Objectives: The purpose of this study was to develop the Pictorial Thai Quality of Life (PTQL), having adequate and sufficient construct validity, discriminant power, concurrent validity, and reliability.
Material and Method: To develop the Pictorial Thai Quality of Life Test, two samples groups were used in the present study: (1) pilot study samples: 30 samples and (2) survey samples were 672 samples consisting of normal, and psychiatric patients. The developing tests items were collected from a review of the literature in which all the items were based on the WHO definition of Quality of Life. Then, experts judgment by the Delphi technique was used in the first stage. After that a pilot study was used to evaluate the testing administration, and wording of the tests items. The final stage was collected data from the survey samples.
Results: The results of the present study showed that the final test was composed 25 items. The construct validity of this test consists of six domains: Physical, Cognitive, Affective, Social Function, Economic and Self-Esteem. All the PTQL items have sufficient discriminant power. It was found to be statistically significant different at the.001 level between those people with mental disorders and normal people. There was a high level of concurrent validity association with WHOQOL-BREF, Pearson correlation coefficient and Area under ROC curve were 0.92 and 0.97 respectively. The reliability coefficients for the Alpha coefficients of the PTQL total test was 0.88. The values of the six scales were from 0.81 to 0.91.
Conclusions: The present study was directed at developing an effective psychometric properties pictorial quality of life questionnaire. The result will be a more direct and meaningful application of an instrument to detect the mental health illness poor quality of life in Thai communities.

Keywords: Development, Pictorial Thai quality of life