Use of the process dissociation procedure to study the contextual effects on face recognition in schizophrenia: familiarity, associative recollection and discriminative recollection.

Contextual effects were explored in schizophrenia patients and paired comparison subjects during a long-term face recognition task. The objective was to investigate the contextual effects on face recognition by manipulating, in the same experiment, the perceptual context of the face (intrinsic vs. extrinsic) and the task context (inclusion vs. exclusion instructions). The situation was derived from the Jacoby's [Jacoby, L.L., 1991. A process dissociation framework: separating automatic from intentional uses of memory. Journal of Memory and Language 30, 513-541] process dissociation procedure. The results showed that schizophrenia patients (N=20) presented lower performances than healthy controls (N=20) in the inclusion but not in the exclusion task. This observation emphasizes the heterogeneity of recollection and suggests that the memory impairment in schizophrenia reflects an imbalance between two mechanisms. The first is a deficit in "associative recollection", i.e., the failure to use efficiently associative information. The other is an enhanced "discriminative recollection" that impedes their capacity to process information separately from its perceptual context. In addition, correlation with symptoms suggest that the former is expressed in the loosening of associations characteristic of disorganization symptoms, whereas the latter reflects the lack of flexibility or the contextualization bias related to psychotic symptoms, i.e., delusions and hallucinations.

Changes in the neuropsychological correlates of clinical dimensions between the acute and stable phase of schizophrenia.

This study was designed to investigate whether the neuropsychological correlates of the symptom dimensions of schizophrenia vary with the clinical state in patients followed from the acute to stable the phase of the illness. Fifteen patients were assessed for symptoms (SAPS-SANS) and undergone a complete neuropsychological assessment at two sessions. The first session (S1) was carried out within six days after admission, i.e., acute phase and the second (S2) at least two month after hospitalization, i.e., stable phase. The data were analyzed using stepwise regression models in which neuropsychological scores were in entered to predict each dimensional score. This analysis was applied on the S1 and S2 data as well as on the S2-S1 difference to assess the neuropsychological predictors of clinical changes. Generally, the results replicate the previous associations between neuropsychological and dimensional measures found in stable patients. In addition, this study shows if each dimension appears to rely on a key structure, symptom variations seems to involve changes in the spread of the dysfunction and/or changes in the connectivity between the key and other regions. The results also suggest that functional changes related to some symptoms dimensions occur to compensate for the dysfunction associated with other symptoms.