Evidence for impaired mnemonic strategy use among patients with schizophrenia using the part-list cuing paradigm

Strategic and mnemonic abilities of person with schizophrenia (SCZ) were studied using a part-list cuing (PLC) task. In this task, presentation of retrieval cues in the form of a subset of studied words typically impairs recall of the remaining items. This impairment is thought to reflect a disruption of participants' natural retrieval strategies.

Participants with SCZ and healthy controls (ns = 28) studied word lists with three different levels of semantic organization: (a) unrelated, (b) categorized, but presented in a random order, and (c) presented by category. For each type of list, participants recalled words under both free-recall and PLC conditions.

Consistent with SCZ-related impairment of strategic retrieval processes, the SCZ group was less disrupted by PLC interference than controls in the unrelated-list condition. Comparison of free recall across lists also indicated a consistent deficit in SCZ despite varying levels of difficulty and retrieval contexts. Nonetheless, the SCZ group demonstrated parallel improvement to the healthy group with increasing list organization.

These results provide evidence of deficient retrieval processes in SCZ in a context placing maximal requirements for utilization of self-initiated, effortful, mnemonic strategies. Unlike most extant results demonstrating mnemonic impairment in persons with SCZ, the present results cannot be accounted for by task difficulty; SCZ participants' recall was less disrupted by PLC than was that of healthy participants. Results also demonstrated that SCZ participants could benefit, in terms of recall and strategy use, from list organization when this structure was explicitly provided at test.