Introduction: Memory deficits in patients with schizophrenia (SZ) are considered as a key feature of the clinical manifestations of the disease. In order to further examine the role and nature of memory deficits in SZ, the pattern of errors in verbal and spatial serial recall tasks committed by SZ patients was compared to that of healthy controls. We also tested the relationship between these memory errors and clinical symptoms.
Methods: Twenty-seven outpatients with recent-onset SZ and 27 age and gender matched healthy controls had to remember sequences of items (digits or localisations) in a serial recall task. Clinical symptoms were assessed with the PANSS and the SAPS.
Results: The results indicate that the number of omissions, intrusions, and transpositions can differentiate patients with SZ from healthy controls. Intrusions and transpositions committed in the verbal domain were associated with the negative subscale of the PANSS. Transposition errors were associated with delusions whether the to-be-remembered information was verbal or spatial.
Conclusion: The examination of the pattern of errors, in particular that of transpositions, is a more informative cognitive index than the mere analysis of overall performance, and provides a promising target for treatment.