Assessing demographic and clinical characteristics and healthcare resource utilization of patients with schizophrenia with inadequate response to antipsychotic treatment

Background: Schizophrenia is a severe mental illness with substantial health, social, and economic impacts. Despite the use of antipsychotics as the standard treatment, many patients fail to achieve an adequate response. This study examined differences in demographics, social determinants of health, treatment patterns, and healthcare resource utilization across antipsychotic response groups. Methods: This retrospective cohort study used electronic health record (EHR) data from the University of Utah Health System (2017–2021). Patients aged 13 years or older with schizophrenia ICD codes and at least one prescribed antipsychotic were classified into adequate response (1 antipsychotic trial), inadequate response (2 antipsychotic trials), treatment-resistant schizophrenia (TRS), (TRS; 3 + antipsychotic trials or clozapine use), or nonadherent. As clozapine is the only antipsychotic approved for TRS management, TRS patients were categorized as clozapine-treated (TRS-C) or without clozapine (TRS-WC). Nonadherent patients were defined as having no providers documentation of taking antipsychotics as prescribed (outside of inpatient hospitalizations). Descriptive statistics and linear regression were used to compare social determinants of health and healthcare resource utilization, including inpatient (IP), outpatient (OP), and emergency department (ED) visits over a one-year follow-up period, and analyzed using linear regression to generate incidence rate ratios. Multivariable regression adjusted for potential confounders. Results: Among 408 patients (mean age 47 years; 72% male; 74% White), 29.9% had adequate response, 32.4% had inadequate response, 9.6% TRS-C, 13.0% TRS-WC, and 15.2% were nonadherent. Homelessness ranged from 8% in TRS-C to 73% in nonadherent patients (p < 0.001). Psychiatric IP visits were higher in inadequate response (IRR = 12.32), TRS-C (IRR = 8.86), and TRS-WC (IRR = 13.04) compared to adequate response (p < 0.001). Psychiatric ED visits were similarly elevated in inadequate response (IRR = 10.86, p < 0.001), TRS-C (incidence rate ratio = 5.47, p = 0.02), and TRS-WC (IRR = 13.81, p < 0.001) when compared to adequate response. Homelessness (IRR = 1.91, 95% CI [1.34–2.72] p < 0.001), Unemployment (IRR = 2.8, 95% CI [1.62–4.84] p < 0.001), and Social Security Disability Insurance (SSDI) enrollment (IRR = 1.83, 95% CI [1.29–2.58] p < 0.001) were all associated with increased all-cause IP visits. Medicare coverage was associated with decreased all-cause IP visits (IRR = 0.51, 95% CI [0.33–0.77] p = 0.002). Conclusion: This study identified significant associations between social and structural conditions (e.g., housing status, incarceration, insurance coverage, and social support) and healthcare resource utilization, alongside differences by demographic and clinical characteristics (e.g., age, comorbidities). Targeted interventions addressing homelessness, improving adherence, and optimizing care pathways are warranted for high-risk subgroups.