Cognitive emotion regulation in methadone maintenance treatment: reliability and validity of the Vietnamese cognitive emotion regulation questionnaire – short version (CERQ-S)

This pilot study aimed to evaluate the Vietnamese version of the cognitive emotion regulation questionnaire – short version (CERQ-S) among patients receiving methadone treatment in Ho Chi Minh City. A pilot study was conducted in 2025, recruited participants from four methadone treatment centers. Content validity was assessed using the Content Validity Index (CVI). Internal consistency was measured by Cronbach’s alpha. Test-retest reliability over a one-month interval was evaluated using the intra-class correlation coefficient (ICC). Descriptive statistics were applied to examine score distributions, floor and ceiling effects. The mean age of 80 participants was 44.3 years (SD=5.5), and the majority were male (88%). All CERQ-S items demonstrated excellent content validity (CVI=1.00). The total scale showed high internal consistency at both time points, and test–retest analyses indicated acceptable short-term temporal stability (overall ICC=0.72). Subscale-level ICCs ranged from moderate to good, with lower stability observed for some domains. Descriptive analyses showed that all subscales covered the full possible score range, with notable floor effects for Catastrophizing and Other-Blame, and generally limited ceiling effects. Exploratory analyses suggested variations in emotion regulation scores across selected sociodemographic characteristics; these findings were interpreted as preliminary. The findings indicate that the instrument is feasible for pilot and descriptive research, while further studies with larger samples are needed to fully evaluate its psychometric properties.