Just came across this very interesting piece by Virginia Hughes in Scientific American about the Indiana Medical History Museum, formerly the pathology department of the Central Indiana Hospital for the Insane, and now back in the news because of a frustrating "dearth of postmortem brain donations from people with mental illness." The solution? Mining genetic information from "old, often forgotten tissue archives".
Though studying old brains is not without challenges, the tissue is free from modern psychiatric drugs, and is, in the words of John Allman, a professor of biology at the California Institute of Technology, "an untapped resource."
To read the entire story, see Shelf-Preservation: Researchers Tap Century-Old Brain Tissue for Clues to Mental Illness