C9orf72 and behavioral variant of frontotemporal dementia: C9orf72 expansion carriers typically show higher rates of NPS, including psychosis and somatic delusions, and more severe psychosis compared with noncarriers.5,81–83 The prevalence of psychotic symptoms among C9orf72 mutation carriers ranges from 21% to 56%, and psychotic symptoms frequently precede behavioral and personality changes characteristic of bvFTD by up to 5 years.5,78 A similar finding of more frequent psychotic symptoms among C9orf72 expansion carriers is also observed across the ALS-FTD continuum.84