New hope is on the horizon for sufferers of multiple sclerosis.
A researcher at Wellington's Victoria University is leading a trial testing two commonly used antipsychotic medications in secondary progressive MS.
One-third of MS sufferers are affected by the form of the disease, for which there is no effective treatment. It can cause significant life-long disability.
The trial, under way at Wellington Regional Hospital, is recruiting for participants, said its leader, Victoria University immunologist Professor Anne La Flamme.
"The majority of agents used to treat the most common form of MS - relapsing remitting MS - were originally used for something else, like viral infections and leukaemia.
"We're looking at two medications, clozapine and risperidone, designed to treat a variety of health disorders such as schizophrenia, bipolar disorder and autism.
"Clozapine and risperidone have always been targeted to mental illness, but our studies show they're able to tone down the immune system in the brain, which is what causes MS.
"This anti-inflammatory action is promising."
Prof La Flamme is working with neurologist Dr David Abernethy, from Capital & Coast District Health Board, and Associate Professor Bronwen Connor, from the University of Auckland.
"The trial will be randomised, blinded and placebo-controlled, to closely monitor any potential adverse effects from the drugs, as well as measure any changes to MS disease," she said.