Neurocognitive assessment in the clinical antipsychotic trials of intervention effectiveness (CATIE) project schizophrenia trial: Development, methodology, and rationale

Patients with schizophrenia are severely impaired in crucial aspects of neurocognitive function. This impairment is the strongest clinical correlate of poor long-term outcome and adaptive dysfunction. Reports of neurocognitive enhancement with second generation antipsychotic medications have thus offered promise for improvement in the long-term outcome of patients with schizophrenia. However, the majority of these studies have had serious weaknesses in methodology, such as open-label design, small samples, or inappropriate dosing of medications. More recent studies have addressed these methodological issues but have been of short duration and have largely been sponsored by pharmaceutical companies. The Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) project is a unique opportunity to address the comparative neurocognitive effectiveness of available antipsychotic medications. This article describes the neurocognitive methods used in the schizophrenia trial of the CATIE project, including the selection and training of neurocognitive raters, patient inclusion criteria for assessment, rationale for the choice of neurocognitive instruments, and methodology for each neurocognitive test.