Psychometric properties of the Persian version of the Reinforcement Sensitivity Theory Personality Questionnaire (RST-PQ)

Background: The Reinforcement Sensitivity Theory of Personality Questionnaire (RST-PQ) originated from the Revised Reinforcement Sensitivity Theory of Personality. This study was conducted to assess the psychometric properties of the Persian version of the RST-PQ among a group of Iranian adults. Method: The cross-sectional study was carried out among 600 Iranian adults utilizing a convenient sampling method, following specific participant selection criteria to enhance the study methodology's transparency (including the age range between 18 and 35 years' participants without major psychiatric diagnoses). Participants completed both the Iranian version of the Reinforcement Sensitivity Theory Personality Questionnaire (RST-PQ) and the Five-Factor NEO-FFI questionnaire. Confirmatory factor analysis, employing the multiple indicators model (MIMIC) approach, was utilized in this study to control for demographic variables such as age and gender. Results: The confirmatory factor analysis results showed an acceptable fit of the proposed six-factor model based on the English version of RST-PQ (CFI = 0.905; RMSEA = 0.053). Also, Cronbach's alpha values confirmed the internal consistency of the proposed structure. In addition, competing models were also used to select the best-proposed model. In this way, different models were evaluated, assuming a change in the correlation intensity between BIS and the Fight-Flight-Freeze System (FFFS). Conclusions: The convergent validity results with the Five-Factor Personality measure provided further support and were consistent with previous research findings. It is crucial to have an Iranian-language version of the RST-PQ to promote RST research and show how this theoretical framework aids in explaining and predicting various actions, whether they are abnormal or healthy.