Background: Despite substantial research on overall decision-making capacity (DMC) levels in schizophrenia, factors causing individuals to make errors during decision-making regarding research participation or treatment are relatively unknown.
Methods: We examined the responses of 84 middle-aged and older patients with schizophrenia or schizoaffective disorder on a structured DMC measure—the MacArthur Competence Assessment Tool for Clinical Research—to determine the frequency and apparent cause of patients’ errors.
Results: Most errors were due to difficulty recalling the disclosed information (seen in 65.5% of patients), particularly the study’s procedures, potential risks/discomforts, and purpose. Errors attributable to concrete thinking, thought disorder or other psychotic symptoms, or perceived coercion were rarer.
Conclusions: Informed consent procedures might be improved for this population by providing information in a way that facilitates learning and memory, such as iterative disclosure of the information, corrective feedback, and emphasis of key points (e.g., the study’s purpose, procedures, and potential risks).