Researchers at Oregon Health & Science University and Portland Veterans Affairs Medical Center say Prozosin appears to block the increase of steroid hormones known as glucocorticoids. Elevated levels of these hormones are linked to atrophy of nerve branches and nerve cell death.

"It's known, from human studies, that corticosteroids are not good for you cognitively," study co-author, Dr. S. Paul Berger, said in a statement. "We think prazosin protects the brain from being damaged by excessive levels of corticosteroid stress hormones."

The researchers said high levels of glucocorticoids in blood serum are associated with such psychiatric conditions as schizophrenia, depression, post-traumatic stress syndrome and Alzheimer's disease and are linked to decreases in cognitive performance in older people not suffering from clinical dementia.

The study was presented at the annual Society for Neuroscience conference in San Diego.