OPRM1 and Alzheimer disease: We demonstrate that (a) in all three independent cohorts, G+ carriers showed anincreased PIT effect; (b) there is no difference between patients with AD and HCs inthe interaction between OPRM1 and PIT; but (c) when merelyinvestigating AD, relapsing patients carrying the G+ allele showed an increased PITeffect as opposed to abstaining patients, who did not show an association betweenOPRM1 genotype and PIT.