Barriers to the appropriate clinical use of medications that improve the cognitive deficits of schizophrenia

A high priority has been placed on developing medications to treat the cognitive deficits associated with schizophrenia, but less attention has been given to planning for appropriate use of these medications in practice. The cognitive deficits of schizophrenia present several complexities as a treatment target that may limit a clinician's ability to prescribe cognitive enhancers to the patients who need them and to monitor for improvements in outcomes. In this review the neuropsychological evidence regarding cognition and functioning is discussed with a view toward how this evidence might guide clinicians' prescribing practices. Three challenges regarding the use of cognitive enhancers in schizophrenia are discussed. First, laboratory constructs of cognition are not equivalent to cognitive skills and behaviors seen in the clinic. The evidence generated in clinical trials of cognitive enhancers may have uncertain ecological validity. Second, objective scores on cognitive tests often do not match clinicians' and patients' perceptions of cognitive deficits. Mismatch between objective and subjective assessments of cognition may complicate the monitoring of medication. Third, although reductions in disability are desired outcomes of cognitive enhancement, clinicians may not be able to rely on assessments of patients' functional status to determine whether cognition medications are effective. In summary, data on the clinical meaning of neuropsychological constructs, careful selection of outcome measures for randomized clinical trials, and effectiveness trials could help ensure that cognition-enhancing medications can be appropriately prescribed in usual practice settings to the patients who can benefit from them.