Prospective memory in patients with first-onset schizophrenia and their non-psychotic siblings

This behavioral study used a dual-task paradigm to compare PM performance in 35 patients with first-onset schizophrenia, 40 non-psychotic siblings and 35 healthy controls. It aimed specifically to examine the effect of schizophrenia group status on PM, the differential effect of group status on PM type, and correlations between PM and other neurocognitive functions and clinical data in first-onset schizophrenia. It also aimed to test the hypothesis that non-psychotic siblings had poorer PM performance than controls. The cohort of first-onset schizophrenia patients had relatively short illness durations (M=1.7 years). The three groups of participants were matched in terms of age, gender and years of education. Results of the study confirmed that first-onset schizophrenia status had a primary effect on PM after controlling for other neurocognitive functions. We also found that first-onset schizophrenia status did not differentially affect two different types of PM. In the first-onset schizophrenia cohort, PM was found to correlate significantly with IQ, executive functions and sustained attention. Finally, contrary to the findings of the previous study, this study did not find siblings of schizophrenia patients to have impaired PM. Taking into account the previous findings of PM in chronic schizophrenia, we concluded that schizophrenia has a primary effect on PM regardless of illness duration.