Video report by ITV News reporter Martha Fairlie
Drugs used to treat cancer and depression could also help slow down the effects of dementia, a new study claims.
If they are proven to work, experts say it is a "very exciting first step in treating these disorders".
Both medicines, one a licensed antidepressant and the other an anti-cancer compound was found to restore protein production in the brains of laboratory mice.
The drugs blocked an important pathway linked to brain cell death caused by prion disorders such as Creutzfeldt-Jakob disease, and dementia.
The drugs used in the study were antidepressant trazodone hydrochloride and anti-cancer drug dibenzoylmethane (DBN).
Professor Giovanna Mallucci, who led the team from the Medical Research Council's Toxicology Unit in Leicester and Cambridge University, said: "We know that trazodone is safe to use in humans, so a clinical trial is now possible.
"We could know in two to three years whether this approach can slow down disease progression, which would be a very exciting first step in treating these disorders.
"Interestingly, trazodone has been used to treat the symptoms of patients in later stages of dementia, so we know it is safe for this group.
"We now need to find out whether giving the drug to patients at an early stage could help arrest or slow down the disease through its effects on this pathway."
Neuropathologist Dr Payam Rezaie, from the Open University, said although the results could represent a significant step forward, it is not a cure.
"Nevertheless, it could represent a significant step forward in attempting to halt these diseases in their tracks.
"And as the researchers state, considering its existing licence for use in elderly patients, trazodone in particular would be a potential candidate for clinical trials moving forward."
Dr David Reynolds, Chief Scientific Officer at Alzheimer’s Research UK, said: “This robust research in mice highlights drugs that could help tackle more than one neurodegenerative disease, but what is true in animals does not always hold true in people.
"Ultimately the only way to see if the drugs identified in this study could help people with these diseases is through clinical trials in people."