Familiarity and recollection processes in patients with recent-onset schizophrenia and their unaffected parents

Abstract

Episodic memory deficits are present in patients with schizophrenia (SZ) and their unaffected relatives and could be considered as a cognitive indicator of genetic vulnerability to SZ. The present study, involving patients with SZ as well as their parents, used experimental tasks specifically designed to disentangle the contribution of familiarity and recollection processes to episodic memory. The performance of patients with SZ (n=26) and their unaffected parents (n=35) was compared with that of healthy control groups matched on socio-demographic variables (controls of patients, n=26; controls of parents, n=35) on two memory tasks assessing recollection and familiarity. The first task was designed to investigate item recognition and memory for item-spatial context associations whereas the second targeted item-item associations. The results revealed an overall episodic memory deficit in patients with SZ, encompassing both familiarity and recollection, while unaffected parents showed a dysfunction restricted to the recollection process. Our study highlights differences and similarities in the source of the episodic memory deficit found in patients with SZ and their unaffected parents, and it suggests that recollection could act as a cognitive endophenotype of SZ. The results also suggest that use of experimental tasks represents a promising method in the search of cognitive endophenotypes in SZ.

Fig. 1

Schematic representation of the experimental task assessing item-context association.

Fig. 2

Mean number of correct responses for the three conditions of the item-spatial context association task for SZ patients (left panel) and unaffected parents (right panel).

Fig. 3

Number of correct responses (hits and correct rejection) for measures of the word pair task for SZ patients (left panel) and unaffected parents (right panel).

Fig. 4

Effect sizes in classical neuropsychological tasks (Trandafir et al., 2006) and experimental tasks from the current study for unaffected relative. Legend: Experimental task from the current study: EXP 1=location (item-spatial association task); EXP 2=correct rejection of rearranged pairs (item-item association task). Classical tasks (Trandafir et al., 2006): CVLT=California Verbal Learning Test, immediate recall; VR(D) =Visual Reproduction (WMS) delayed recall; VR (I)=Visual Reproduction (WMS) immediate recall; LM(D)=Logical Memory (WMS) delayed recall; LM(I)=Logical Memory (WMS) immediate recall; VPA(I+D)=Verbal Paired Associates (WMS) immediate and delayed recall. The red line represents the cut off for large effect size.