Prospective memory in schizophrenia: The impact of varying retrospective-memory load

Abstract

The present study investigated event-based prospective memory in individuals with schizophrenia (n = 23) and healthy controls (n = 23). The retrospective-memory load was varied to disentangle the relative contributions of the retrospective and prospective components on prospective-memory functioning. A generalized prospective-memory deficit in schizophrenia emerged, with significant impairment evident even when retrospective-memory demands were minimal. Exploratory analyses suggest that both the retrospective and the prospective components contribute to the prospective-memory deficit in schizophrenia.

Keywords:

• Cognition
• Executive function
• Prospective memory
• Retrospective memory
• Schizophrenia

Notes

¹As the percentage accuracy levels for participants showed a skewed distribution of scores, we reanalyzed data with arcsin transformation of these scores. This, however, did not change the results.

²We thank two anonymous reviewers for suggesting these analyses.

³We chose to proceed with only one control group since only two (low RM load) and three controls (high RM load), respectively, showed a deficient retrospective memory for the PM cues.

⁴Reanalyzing neuropsychological assessment data indicated no group differences between RM correct and RM incorrect individuals with schizophrenia in education, disease duration, and baseline cognitive functioning.

⁵A potential limitation of the present study is that there are no reliability data available on the specific task version applied; however, other studies using similar prospective-memory tasks with also three to four PM cues report satisfactory reliability (e.g., Salthouse, Berish, & Siedlecki, 2004; Zeintl, Kliegel, & Hofer, in press).

⁶One might argue that early aging studies excluded participants with incorrect target recall. However, this was done to experimentally rule out any influence of the RM component in order to most purely study the prospective component and to demonstrate that PM is different from RM. Importantly, the present study explicitly aimed at investigating the contribution of both the prospective and retrospective component and therefore considers retrospective failures of participants with schizophrenia an important aspect of the empirical pattern.