Verbal memory intrusions in schizophrenia: associations with self-reflectivity, symptomatology, and neurocognition

Verbal memory deficits commonly observed among patients with schizophrenia include the tendency to commit intrusion errors (i.e., the incorrect recall of task-irrelevant material). Intrusion errors have been linked to deficits in self-monitoring, increased positive and disorganized symptoms, and poor executive functioning in these individuals, but such associations are inconsistent across studies. Accordingly, the purpose of the present study was to investigate further these relations in patients with schizophrenia. Seventy-nine patients with schizophrenia-spectrum disorders were grouped according to their number of intrusions on a verbal recall task (no intrusions, n=54; two or more intrusions, n=25) and compared on measures of metacognitive self-reflectivity (i.e., the ability to reason about one's own mental states), positive and disorganized symptomatology, and executive functioning. After controlling for overall verbal memory performance, the intrusion group exhibited less self-reflectivity and more disorganized symptoms and performed more poorly on neurocognitive measures sensitive to executive dysfunction, relative to the no-intrusion group. Hierarchical logistic regression controlling for overall verbal memory performance indicated that only self-reflectivity and disorganized symptoms significantly predicted group membership. These data suggest that verbal memory intrusions are linked to deficits in the ability to identify, organize, and reason about one's own thoughts in patients with schizophrenia.