Understanding Mechanisms of Synaptic Degeneration Underlying Clinical Symptoms in Patients With MDs and NDs.

Inclusion criteria for psychiatric disorders: * Age group: Midlife brain donors (age-at-death\>40). * Sex distribution: % Female in schizophrenia (23%), major depressive disorder and controls (40%), bipolar disorder and controls (55%). These percentages match those typically found in these disorders. * Antemortem diagnosis of schizophrenia (paranoid-subtype diagnoses only to minimise the impact of potential confounding factors on the results and ensure homogeneity across schizophrenia subjects), major depression or bipolar disorder. Diagnoses are confirrmed antemortem by a psychiatrist using Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) criteria, as recorded in the deceased individuals' medical records. Exclusion criteria for psychiatric disorders: For schizophrenia, cases displaying additional neurological or psychiatric conditions, such as histories of substance use disorder will be excluded. Postmortem delay \>24h (to minimise perimortem confounding variables potentially affecting tissue quality. Inclusion criteria for Neurodegenerative diseases: * Age group: Latelife brain donors (age-at-death\>50). * Sex distribution: Alzheimer's disease (60%), frontotemporal dementia (65%). These percentages match those typically found in these diseases. * Neuropathological confirmation of Alzheimer's disease or frontotemporal lobar degeneration (C9orf72 repeat expansion carrier)Alzheimer's disease Exclusion criteria for Neurodegenerative diseases:…