Tiny flatworms which usually live in ponds, rivers and streams could replace lab rats in the development of treatments for schizophrenia, drug addiction and other mental health disorders, after scientists discovered the worms react to certain drugs in a similar way to rodents.
The worms come from a family known as planaria, with some species previously thought to be “immortal” due to their unique regenerative abilities, which includes the ability to regenerate lost body parts, including entire brains.
A team of scientists at the University of Reading gave the worms haloperidol, a drug used to treat mental health conditions, and found the worms became much less active, just like mice and rats do.
Previous studies have used planaria to research epilepsy treatments and to investigate drug addiction, as the flatworms exhibit signs of withdrawal symptoms. This new study could help to develop treatments for mental health conditions such as schizophrenia and hallucinations.
A 2024 study reported that one in 69 UK adults are using anti-psychotic medication long-term.
Professor Vitaliy Khutoryanskiy, who led the study from the University of Reading, said: “This finding adds to growing evidence that tiny flatworms like planaria could play a valuable role in how we study the brain. They display certain responses to psychiatric drugs that resemble those seen in mammals, but using them involves far fewer ethical concerns.”
According to UK government data, 882,000 mice and 144,060 rats were used in animal research in 2023. A 2016 study suggested the use of rats and mice in neuroscience had risen from 20 per cent in the 1980s, to over 50 per cent by the 2010s.
Despite efforts to make research more ethical, scientists still rely heavily on rodents for testing. The researchers said using flatworms for studying brain conditions could potentially reduce the number of rodents used by scientists.
Professor Khutoryanskiy added: “Close to a million mice and rats are used in UK research each year, but using planaria instead could potentially cut those numbers and still give us the answers we need to develop better treatments for people with serious mental health conditions. It’s good for science and it’s good for animal welfare.”
The research is published in the journal Pharmaceutical Research.
