Quantification of treatment response is crucial to optimize outcomes for patients with schizophrenia. In this study, we evaluated the relationship between quantitative measures of clinician-rated symptom severity and self-rated side effects, well-being, and functioning among inpatients with schizophrenia using the six-item version of the Positive and Negative Syndrome Scale (PANSS-6), the Glasgow Antipsychotic Side-effect Scale (GASS), the WHO-Five Well-being Index (WHO-5), and the Sheehan Disability Scale (SDS). All measurements were conducted as close to admission and discharge as possible. Well-being and functioning were found to be most strongly associated with the additive effect of symptoms and side effects, while changes in side effects, well-being, and functioning appeared to be relatively independent from changes in symptom severity. The use of both symptom and side effect measures should inform clinical decision-making in the treatment of schizophrenia, as it has the potential to optimize functioning and well-being.© 2023. The Author(s).