Tau Biomarkers in Late-onset Psychosis (LOP)

This study is investigating whether brain protein changes (tau biomarkers) associated with Alzheimer's disease are also present in older adults who develop psychosis for the first time late in life — a condition called late-onset psychosis. Understanding this link could improve diagnosis and care. **You may be eligible if...** - You are between 65 and 85 years old - You have been diagnosed with late-onset schizophrenia-like psychosis or delusional disorder - A caregiver is available to provide additional information about your history - Your cognitive function is largely intact (MMSE score of 24 or higher, CDR of 0 or 0.5) - Your memory tests are within the normal range (ruling out MCI) **You may NOT be eligible if...** - You have significant hearing difficulties - You have a dementia diagnosis or score below the normal range on cognitive tests - You are unable to participate in neuropsychological assessments - You have other neurological conditions that better explain your symptoms Talk to your doctor to see if this trial is right for you.