Treatment decision making in patients with bipolar and schizophrenia spectrum disorders: a comparison

This study investigates the decision-making capacities of patients with bipolar disorder (BD) and schizophrenia spectrum disorders (SSD), focusing on differences across four dimensions assessed by the MacArthur Competence Assessment Tool for Treatment (MacCAT-T): Understanding, Appreciation, Reasoning, and Expressing a Choice. A total of 398 patients (237 SSD and 161 BD) were included, with data collected from both inpatient and outpatient settings. Patients with SSD exhibited greater psychopathological severity, were predominantly male, and had a lower level of education compared to BD patients. No significant differences were found between groups in Understanding, Reasoning, or Choice dimensions of the MacCAT-T. However, BD patients scored higher in the Appreciation domain, indicating a better ability to recognize the relevance of medical information to their personal circumstances. Psychopathological severity, measured by the Brief Psychiatric Rating Scale (BPRS) and Positive and Negative Syndrome Scale (PANSS), significantly influenced MacCAT-T scores. In SSD patients, conceptual disorganization and lack of judgment negatively impacted decision-making, while BD patients were adversely affected by somatic concerns and hostility. Cognitive impairments, particularly in SSD, appeared to contribute to differences in the Appreciation domain. The study highlights the influence of psychopathology on decisional capacity in severe mental illness, with implications for tailored clinical interventions. Despite similar overall capacity levels between groups, further research is needed to explore the role of cognitive and contextual factors in shaping these abilities. These findings support the use of standardized tools to guide clinical assessments and ensure informed decision-making in psychiatric care.