Assessment of Linguistic Equivalence and Internal Consistency of the Culturally Adapted Bangla Version of the Glasgow Antipsychotic Side-Effect Scale (GASS-B)

Open Access

Abstract

Background: Antipsychotic medications frequently cause a spectrum of adverse effects, which can reduce adherence and impact patient outcomes. The Glasgow Antipsychotic Side-Effect Scale (GASS) is a widely used self-administered tool to monitor these side effects, but no validated Bangla version exists. Aim of the study: To assess the linguistic equivalence, reliability, and validity of the culturally adapted Bangla version of the GASS (GASS-B) among adult patients receiving antipsychotics in Bangladesh. Methods & Materials: A cross-sectional study was conducted among 220 adult patients at the National Institute of Mental Health, Dhaka. Standardized translation, back-translation, expert review, and pilot testing procedures were employed. Data were analyzed using SPSS version 24. Descriptive statistics (frequencies, percentages, means, SDs) summarized variables. Reliability was assessed via Cronbach’s alpha, split-half reliability, and intraclass correlation coefficient (ICC). Validity was evaluated through face validity (expert review), content validity (Content Validity Index), and construct validity (confirmatory factor analysis and principal component analysis). Results were presented in tabular and graphical formats. Result: The GASS-B demonstrated acceptable internal consistency (α = 0.745), good test–retest reliability (ICC = 0.82), and strong content validity (I-CVI 0.83–1.00). Factor analyses supported a seven-factor structure explaining 58.9% of variance, confirming construct validity. Conclusion: The GASS-B is a linguistically and culturally valid, reliable, and practical tool for assessing antipsychotic side effects in Bangla-speaking patients, facilitating improved clinical monitoring and adherence.