Psychometric Properties and Contribution to Mental Health of the Bulgarian version of the 4-Factor Ruminative Thought Style Questionnaire.

Background: The Ruminative Thought Style Questionnaire (RTSQ) is a multifaceted measure of general trait rumination. However, there is no instrument for measuring rumination in Bulgarian, which limits progress in the field.

Aim: We aimed to validate the RTSQ in Bulgarian and examine its psychometric properties and contribution to several mental health outcomes.

Materials And Methods: We sampled 529 undergraduate students (18 – 35 years; 33.6% male; 80.9% Bulgarian) from the Medical University in Plovdiv, Bulgaria. They completed a questionnaire asking about rumination (RTSQ), mental health, and sociodemographic information. The RTSQ was first translated to Bulgarian. Its internal consistency was assessed with Cronbach’s alpha. Confirmatory factor analysis was performed on the 4-factor RTSQ, and multi-group CFA examined its measurement invariance. Structural equation modelling was used to test the relations between the RTSQ factors, depression, anxiety, and resilience to stress.

Results: The RTSQ had acceptable internal consistency (α ≥ 0.8) and its 4-factor model had good fit to the data. In addition, its measurement invariance was supported across languages and cultures of administration. We observed differential associations with depression, anxiety, and resilience, with some of the RTSQ factors emerging as maladaptive (problem-focused thoughts and repetitive thoughts), while others as neutral (anticipatory thoughts) or potentially supportive of resilience (counterfactual thinking).

Conclusion: The RTSQ was successfully validated in Bulgarian and represents a reliable measure of trait rumination. It could be useful in gaining further insight into strategies adopted by individuals to cope with stressors and could help develop interventions supporting healthy coping styles. These findings should be replicated in other non-clinical/clinical populations.