Quality of life, disability and antipsychotics-related side effects in schizophrenia spectrum and bipolar disorder: the role of patient-reported outcome measures

Abstract Background Schizophrenia and bipolar disorder significantly impair daily functioning and quality of life. Effective treatment monitoring requires tools assessing both clinical symptoms and everyday impairment. Aim This cross-sectional study explored relationships between symptoms, side effects, and functioning using clinician-rated and patient-reported measures. We examined whether the Glasgow Antipsychotic Side-Effect Scale (GASS), a patient-reported outcome measure (PROM), is associated with disability and quality of life comparably to the clinician-administered Udvalg for Kliniske Undersøgelser (UKU) Side Effect Rating Scale. Methods We recruited 100 individuals with schizophrenia spectrum or bipolar disorders receiving antipsychotic treatment. Linear regressions and network analyses were conducted. Linear regressions assessed the association between side effects, disability (World Health Organization Disability Assessment Schedule, WHODAS) and quality of life (EuroQol 5-Dimension scale, EQ-5D). Network analyses were conducted to explore the interplay between side effects, disability, quality of life and symptoms, the latter assessed using the Positive and Negative Syndrome Scale (PANSS), Young Mania Rating Scale (YMRS), and Montgomery–Åsberg Depression Rating Scale (MADRS). Results Side effects assessed with GASS and UKU significantly impacted disability (GASS: p  < .001, 95% CI [0.274; 0.635]; UKU: p  < .001, 95% CI [0.313; 1.021]) and reduced quality of life (GASS: p  < .001, 95% CI [-1.391; -0.511]; UKU: p  < .001, 95% CI [-3.176; -1.668]). Network analysis identified depressive symptoms as central in the UKU network and autonomic side effects as central in the GASS network. Conclusion GASS total and subgroup scores showed comparable associations with disability and quality of life as UKU. Integrating both perspectives enables comprehensive monitoring and patient-centred care.