Past studies have suggested depression and other neuropsychiatric symptoms may be predictors of Alzheimer's disease's progression during its "preclinical" phase, during which time brain deposits of fibrillar amyloid and pathological tau accumulate in a patient's brain. An association between elevated amyloid beta levels and the worsening of anxiety symptoms has been identified by recent research. The findings support the hypothesis that neuropsychiatric symptoms could represent the early manifestation of Alzheimer's disease in older adults.