GFAP and Mental deterioration: Adding NPS and the plasma biomarkers to a reference model improved the prediction of future NPS (AUC 0.73 to 0.84, p=.007) and AD pathology (AUC 0.79 to 0.86, p=.006), but not of cognitive decline (AUC 0.79 to 0.84, p=.068).<h4>Conclusion</h4>Plasma GFAP is associated with NPS while NfL and GFAP are both associated with future NPS and NPS severity.