Tau Biomarkers in Late-onset Psychosis (LOP)

Inclusion Criteria: 1. Male or female, aged 65-85 years. 2. Diagnosis of late-onset non-affective primary psychotic disorder consistent with either very late-onset schizophrenia-like psychosis (VLOSP, International Late-Onset Schizophrenia Group consensus criteria, Howard et al., 2000) or delusional disorder (DSM-5 criteria) 3. Caregiver available to provide collateral history and participation in informant-based ratings (NPI,CDR) 4. Clinical Dementia Rating (CDR) score of 0 or 0.5. 5. Mini-Mental State Examination (MMSE) score ≥ 24 and at the screening visit. 6. Normal memory function (to rule-out mild cognitive impairment, MCI) documented by scoring within 1.5 SD range in education adjusted norms of the Logical Memory II subscale 7. Ability to hear 500, 1000 and 1500 Hz bilaterally on a hearing evaluation (hearing aids permitted). Exclusion Criteria: 1. Participants with affective and psychotic disorders including bipolar disorder, schizoaffective disorder, active major depression; insulin dependent type 2 diabetes; a history of CVD; a history of epilepsy; a history of TBI with greater than 15 minutes of loss of consciousness; a movement disorder including Parkinson's disease; stroke; autoimmune disease affecting the CNS; substance abuse disorder; or active delirium/encephalopathy. 2. Evidence of a clinically relevant neurological disorder 3. Modified Hachinski ischemia score of more than 4. 4. History of alcoholism or drug dependency/abuse within the last 5 years before screening. 5. Presence of metal implants such as pacemakers, ear implants, internal bullet fragments or shrapnel. 6. Inability to lie flat for 1 hour approximately. 7. Hearing impairment as evidenced by the inability to hear 500, 1000 and 1500 Hz bilaterally on a hearing evaluation. Subjects with hearing aids will be allowed to participate if they meet minimum hearing requirements.