Abstract

Inhibition of return (IOR) refers the effect that people are slower to detect a target that appears at the same location of a previous event than when it appears in a new location. Recent studies investigating IOR in patients with schizophrenia have had conflicting results and there is no published study examining IOR in older schizophrenia patients. In an attempt to add clarity IOR in patients with schizophrenia and to probe IOR in older schizophrenia patients, this study examined IOR in young and old patients diagnosed with schizophrenia who are exhibiting severe symptomology and therefore require tertiary mental health care. A typical exogenous cuing paradigm with two stimulus onset asynchronies (SOAs) of 200 and 600 ms was used to observe the typical biphasic effects: an early facilitation and a later IOR. As expected, the control group showed a significant facilitation at 200 ms SOA, and a significant IOR effect at 600 ms SOA for both age groups. In contrast, the patient group showed facilitation at both 200 and 600 ms SOA for both age groups. This result suggests that IOR is absent in patients with schizophrenia and that they exhibit continued facilitation. Moreover, IOR appears to be an age-resistant effect in the control group and the lack of IOR in the patient group is not related to age either. Furthermore, the lack of IOR in patients with schizophrenia was not related to their psychopathology symptoms, cognitive dysfunctions, and overall severity of illness.