Verbal memory improvement in first-episode psychosis APOE-ε4 carriers: a pleiotropic effect?

Background Verbal memory impairment is a core feature in schizophrenia even at early stages of the disease, but its etiopathogenesis is not fully understood. The APOE-e4 is the main genetic risk factor for late-onset Alzheimer’s disease. Our primary goal was to ascertain whether APOE-e4 status had a pleiotropic effect in early stages of the illness. Participants and methods A total of 86 first-episode psychosis (FEP) outpatients and 39 healthy volunteers were recruited. Demographic and clinical data, APOE genotyping, and a neuropsychological test battery including the California Verbal Learning Test – second edition (CVLT-II) were administered and assessed at study entry and at 1-year follow-up. Data were analyzed using mixed-model repeated measures, where the dependent variable was verbal memory indexed by California Verbal Learning Test (CVLT) Trials 1–5 total recall score. Results FEP-APOE-e4 carriers and FEP-APOE-e4 noncarriers had similar symptom severity, clinical outcomes, premorbid and current intelligence quotient, and exposure to antipsychotics. There was a main effect of group on CVLT 1–5 (FEP =43.30 vs control =58.25; F[1, 119.7]=42.97; P