Adaptation and validation of the Glasgow Antipsychotic Side-Effect Scale in Bangladesh

This study aimed to adapt and validate the Glasgow Antipsychotic Side-Effect Scale (GASS) in Bangla.

Patients aged ≥18 years with a psychiatric disorder who were currently taking antipsychotics were recruited from a tertiary care psychiatric hospital using convenience sampling. Additionally, patients aged ≥18 years with a psychiatric disorder who had not received any antipsychotic medications in the past 6 months were recruited as controls. Participants were assessed using the newly adapted GASS Bangla. Internal consistency was assessed using McDonald's omega. Principal component analysis with varimax rotation was used to determine the factor structure. Discriminant validity was examined.

In total, 153 male and 67 female patients (mean age, 27.8 years) who were receiving antipsychotic medications were included. The most common diagnoses were schizophrenia spectrum disorders (49.1%) and bipolar disorders (46.8%). The median duration of illness was 36 months, and the median duration of antipsychotic medication was 4 months. Additionally, 29 male and 21 female controls (mean age, 30.2 years) were included. The mean GASS Bangla score of the patients was 13.3 ± 8.4. Among the 220 patients, 181 (82.3%) reported absent or mild adverse effects, 34 (15.5%) reported moderate adverse effects, and five (2.3%) reported severe adverse effects. In contrast, all controls reported either absent or mild adverse effects. Patients taking antipsychotic medication had higher median GASS Bangla scores than controls (12 vs 2, p < 0.001), supporting the scale's discriminant validity. Internal consistency of the GASS Bangla was moderate (McDonald's omega = 0.604). Factor loadings ranged from 0.040 to 0.573, with most items loading above the conventional threshold of 0.30. Principal component analysis revealed a seven-factor structure that explained 58.9% of the total variance.

The GASS Bangla is a user-friendly instrument for use as a screening tool. Despite moderate internal consistency, its clinical relevance and strong discriminant validity support its application in clinical practice.