Episodic memory impairment in children and adolescents at risk for schizophrenia: A role for context processing

Abstract

People with schizophrenia experience episodic memory impairments that have been theorized to reflect deficits in processing context (e.g., spatio-temporal features tied to a specific event). Although past research has reported episodic memory impairments in young people at-risk for schizophrenia, the extent to which these impairments reflect context processing deficits remains unknown. We addressed this gap in the literature by examining whether children and adolescents at risk for schizophrenia exhibit context processing deficits during free recall, a memory task with high contextual demands. Our sample included three groups (N = 58, 9-16 years old) varying in risk for schizophrenia:16 high-risk, unaffected first-degree relatives of patients with schizophrenia, bipolar disorder, and/or schizoaffective disorder, 22 clinical control participants with a comorbid disorder (ADHD and/or an anxiety disorder), and 20 healthy control participants. Participants first completed a free recall task and then completed a recognition memory task. Based on established theories of episodic memory, we assumed that context processing played a more pivotal role in free recall than recognition memory. Consequently, if schizophrenia risk is associated with context processing deficits, then memory impairment should be present in free recall measures that are most sensitive to context processing (i.e., recall accuracy and temporal contiguity). Consistent with this prediction, free recall accuracy and temporal contiguity were lower for the high-risk group than the healthy controls, whereas recognition memory was comparable across groups. These findings suggest that episodic memory impairments associated with schizophrenia in unaffected, first-degree relatives may reflect context processing deficits.

Keywords: Cognitive impairments; Context processing; Episodic memory; Schizophrenia.

Fig. 1

Correct recall across risk groups and trials. Note. (A) Correct recall averaged across trials was significantly lower for the high-risk than other groups. (B) This nominal pattern was consistent across all five trials. Group means are shown as the heights of white diamonds (A) and bars (B), and corresponding error bars are 95% confidence intervals. (A) Medians and interquartile ranges are displayed in boxplots. Distributional information is shown as individual participant estimates (dots) and the approximated frequencies of those estimates displayed as kernel probability densities (the width of corresponding half violin plots).

Fig. 2

Lag conditional response probabilities across risk groups. Note. Conditional response probabilities estimated from a mixed effect model. The lags only ranged from −3 to 3 because there were sparse observations at longer lags. Error bars are 95% confidence intervals. The probabilities for recalls from adjacent input positions (−1 and 1) were significantly lower for the high-risk group than the clinical control and healthy control groups.

Fig. 3

Recognition sensitivity and response bias across risk groups. Note. There were no significant between-group differences in (A) sensitivity (computed as d′) or (B) response bias (computed as c). Group means are shown as white diamonds and corresponding errors bars are 95% confidence intervals. Medians and interquartile ranges are displayed in boxplots. Distributional information is shown as individual participant estimates (dots) and the approximated frequencies of those estimates displayed as kernel probability densities (the width of corresponding half violin plots).