Working Memory Capacity and Psychotic-Like Experiences in a General Population Sample of Adolescents and Young Adults

Tim B Ziermans

doi:10.3389/fpsyt.2013.00161

Abstract

Working memory (WM) impairment is a common feature in individuals with schizophrenia and high-risk for psychosis and a promising target for early intervention strategies. However, it is unclear to what extent WM impairment parallels specific behavioral symptoms along the psychosis continuum. To address this issue, the current study investigated the relation of WM capacity with psychotic-like experiences (PLEs) in a large Swedish population sample (N = 1012) of adolescents and young adults (M = 24.4 years, range 12–35). WM was assessed with two online computer tasks: a task where participants had to identify and remember the location of an odd shape and a task of remembering and following instructions. PLE scores were derived from a translated symptom questionnaire (Community Assessment of Psychic Experiences), which includes positive, negative, and depressive symptom scales. Positive and negative symptom scales were further subdivided into symptom clusters based on factor analyses. The results showed that low WM capacity was modestly associated with increased reports of bizarre experiences (BE) and depressive symptoms, after controlling for age, gender, and global symptom scores. Interestingly, when analyses were repeated for separate age groups, low WM was exclusively associated with a higher frequency of BE for young adults (20–27 years) and with depressive symptoms for older adults (28–35 years). These findings suggest that specific PLEs can be indicative of reduced WM capacity in early adulthood, which in turn may reflect an increased risk for psychosis and a greater need for targeted intervention. In contrast, during adolescence individual differences in cognitive development may influence the strength of the relationships and thereby mask potential vulnerabilities for psychopathology.

Highlights

Working memory (WM) refers to the cognitive function to retain and manipulate information over a brief period of time
Fourteen participants did not meet the age criterion and 10 additional adolescents were excluded after verification that a parent had either partially or completely filled out the Community Assessment of Psychic Experiences (CAPE) on their behalf
Understanding how cognitive functions relate to behavioral symptoms in the general population can provide further insight into underlying mechanisms of emerging psychopathology and lead to identification of early intervention targets

Summary

Introduction

Working memory (WM) refers to the cognitive function to retain and manipulate information over a brief period of time. Meta-analytic evidence supports that impairments in WM, as well as in a wide range of other neurocognitive domains, are a common feature among individuals suffering from schizophrenia [6], schizoaffective disorders [7] and, to a lesser extent, young individuals at clinical high-risk for developing a psychotic disorder [8]. Most high-risk studies only recruit help-seeking individuals and rely on categorical group comparisons defined by clinical cut-off scores These strategies are unfit to address whether WM is associated with sub-clinical symptomatology in the population at large as well. Given the recent surge of interest in WM training programs as an intervention aid in early schizophrenia and high-risk populations [9, 10], it is critical to improve our understanding of the putative relationship between WM performance and psychotic-like symptomatology in order to optimize their use and efficacy

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