Intra-individual variability across neuropsychological tasks in schizophrenia: A comparison of patients, their siblings, and healthy controls

Recently, higher degrees of intra-individual variability (IIV) across neuropsychological tasks have been linked to risk for developing schizophrenia. Extending these findings to examine not only disease risk but genetic susceptibility to schizophrenia, we examined IIV across five factor-based cognitive scores in a sample of schizophrenia patients, their unaffected siblings, and healthy volunteers. IIV was significantly different among probands, siblings, and controls, with groups showing decreasing variability in that order. In addition, modest associations between IIV, age, and functioning ability were found. In light of these results, IIV indices might represent useful tools in understanding cognition in schizophrenia.