Psychometric Study Using Item Response Theory of an Instrument Developed for Assessment of Iranian Mental Health Problems

Abstract

Background: Currently, in addition to the undeniable impact of cultural factors on mental health problems’ diagnosis and treatment methods, the use of rapid, short, and intervention-based instruments can be effective in the accurate diagnosis of mental health problems, especially in the health system of developing countries. Objectives: This study aimed to validate an instrument developed for screening patients with common mental health problems using item response theory (IRT). Methods: The study was conducted in Semnan province (with Persian ethnicity), Iran, from August 2017 to February 2018. A 101-item tool consisted of district common mental health problems (i.e., depression, anxiety, and obsession), along with a functional checklist. The development of the instrument involved a pilot study and psychometric testing. The IRT-based analysis was used as the item-reduction method to evaluate the shortened tool as an appropriate screening tool. The participants were healthy individuals and patients with depression, anxiety, and obsessive-compulsive disorder (OCD). The data were analyzed using Stata software (version 15.1). Results: The study participants were 160 individuals (58.2% male) with a mean age of 36.3 ± 11.2 years. All item impact factors were within the range of 1.8 - 5. The mean values of clarity, simplicity, relevance, and scale-level content validity index/averaging calculation method of the instrument were 96.73 ± 0.70, 97.64 ± 0.61, 98.2 ± 1.9, and 97.09 ± 0.63, respectively. Cronbach’s alpha and internal consistency coefficient were 0.88 and 0.7. Moreover, 13, 5, and 12 items were excluded using IRT from depression, anxiety, and OCD dimensions based on the threshold criteria, respectively. Conclusions: Iranian screening tools for mental health problems can provide qualified information with the least error and the most precision in appropriate early diagnosis and decrease the burden of mental health problems in the national healthcare system.