Functional mechanisms underlying impaired recognition memory and conscious awareness in patients with schizophrenia

Schizophrenia impairs episodic memory in its critical feature, autonoetic awareness, i.e., the type of awareness that is characterized by mentally reliving events from one's personal past. It spares noetic awareness, another form of awareness based on feelings of familiarity. We investigated the hypothesis that the impairment of autonoetic awareness is related to defective information that binds together separate aspects of events.

An experiential approach to recognition memory was used. Twenty-five patients with schizophrenia and 25 normal subjects performed or watched actions consisting of pairing objects. Then, they had to recognize pairs of objects and who paired them (source recognition). Subjects were also asked to provide a "remember" (autonoetic awareness) or a "know" (noetic awareness) response according to their subjective state at the time they recognized each pair of objects and each source.

Patients exhibited an impaired recognition memory. When actions were observed, recognition of pairs of objects, but not of source, was no better than chance. There was a reduction in frequency of autonoetic awareness, its consistency throughout recognition of objects and source, and its relationship to source discrimination accuracy. Recognition was based largely on noetic awareness.

Patients with schizophrenia are unable to link the separate aspects of events into a cohesive, memorable, and distinctive whole. The corollary of this defective relational binding is a quantitative and qualitative impairment of autonoetic awareness.