Paired-associate learning and memory interference in schizophrenia

Patients with frontal lobe damage have been shown to exhibit disproportiona te impairments of second list learning as a result of interference effects. Based upon the assumption that schizophrenia is associated with frontal dy sfunction, we attempted to explore how various manipulations of paired-asso ciate learning tasks would interfere with schizophrenic patients' memory pe rformance. Patients with schizophrenia were administered four tests of pair ed-associate learning, in which cue and response words were manipulated to increase interference across two study lists. In two tests of paired-associ ate learning (AB-AC lest), cue words used in one list were repeated in a se cond list but were associated with different response words (e.g. lion-hunt er, lion-circus). One version of this test employed moderately related word pairs and the other version employed unrelated word pairs. In the other tw o tests (AB-ABr test), all words used in one list were repeated in a second list but were rearranged to form new pairs. Again, one version of this tes t used moderately related word pairs and the other version used unrelated w ord pairs. We hypothesized that patients with schizophrenia would exhibit d isproportionate impairment of second-list learning as a result of interfere nce effects and that they would do especially poorly in the AB-ABr task, wh ere the word pairs were unrelated. However, these predictions were not supp orted. Furthermore, it was difficult to tease apart a specific problem in l ist discrimination from the generally poor memory of the schizophrenic pati ents. We suggest that the susceptibility to these interference effects in p atients with schizophrenia is not a specific problem in cognition, but rath er one that is confounded by general memory problems. (C) 2000 Elsevier Sci ence Ltd. All rights reserved.