Decision-making capacity for research participation among individuals in the CATIE schizophrenia trial
OBJECTIVE: Uncertainty regarding the degree to which persons with schizophrenia may lack decision-making capacity, and what the predictors of capacity may be led us to examine the relationship between psychopathology, neurocognitive functioning, and decision-making capacity in a large sample of persons with schizophrenia at entry into a clinical trial.
METHOD: In the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) schizophrenia trial, a clinical trial sponsored by the National Institute of Mental Health designed to compare the effectiveness of antipsychotic drugs, subjects were administered the MacArthur Competence Assessment Tool-Clinical Research (MacCAT-CR) and had to demonstrate adequate decision-making capacity before randomization. The MacCAT-CR, the Positive and Negative Syndrome Scale (PANSS), and an extensive neurocognitive battery were completed for 1447 study participants.
RESULTS: The neurocognitive composite score and all 5 neurocognitive subscores (verbal memory, vigilance, processing speed, reasoning, and working memory) were positive correlates of the MacCAT-CR understanding, appreciation, and reasoning scales at baseline. Higher levels of negative symptoms, but not positive symptoms, were inversely correlated with these three MacCAT-CR scales. Linear regression models of all three MacCAT-CR scales identified working memory as a predictor; negative symptoms made a small contribution to the understanding and appreciation scores.
CONCLUSIONS: Negative symptoms and aspects of neurocognitive functioning were correlated with decision-making capacity in this large sample of moderately ill subjects with schizophrenia. In multiple regression models predicting performance on the MacCAT-CR scales, working memory was the only consistent predictor of the components of decision-making capacity. Individuals with schizophrenia who have prominent cognitive dysfunction, especially memory impairment, may warrant particular attention when participating in research.
Stroup, S., Appelbaum, P., Swartz, M., Patel, M., Davis, S., Jeste, D., ... Lieberman, J. (2005). Decision-making capacity for research participation among individuals in the CATIE schizophrenia trial. Schizophrenia Research, 80(1), 1-8. DOI: 10.1016/j.schres.2005.08.007