Open magnetic resonance imaging datasets on psychosis?
The Australian Schizophrenia Research Bank (http://www.schizophreniaresearch.org.au/bank/research-information/information-on-datasample-availability-for-researchers/) has an 'open' database of clinical MRI (T1s and DTI) as well as healthy controls. Access isn't free though - they charge an administration fee to cover costs. It is an ongoing effort and I think there is about 500 MRIs from patients in there now, but I'm not sure what the latest numbers are exactly.