Tiny pond worms could be used to help find new treatments for schizophrenia, study says

Tiny flatworms that normally wriggle unnoticed in ponds and rivers may hold the potential to help scientists develop new treatments for schizophrenia and addiction – while dramatically reducing the number of mice and rats used in medical research.

In a new study, researchers from the United Kingdom found that planaria, harmless worms just a few millimetres long, respond to psychiatric drugs in ways that are very similar to mammals.

When given haloperidol – an antipsychotic drug used to treat schizophrenia – the worms became sluggish and inactive, just as lab mice and rats do.

The findings, published in Pharmaceutical Research, suggest these simple organisms could help scientists probe the effects of medicines on the brain without using rodents.

"This finding adds to growing evidence that tiny flatworms like planaria could play a valuable role in how we study the brain," said Vitaliy Khutoryanskiy, one of the study's authors and a professor at the University of Reading.

He added that using these flatworms in research "involves far fewer ethical concerns" than mice and rats.

Neuroscientists have become increasingly reliant on rodents for brain research over the past four decades. In the UK alone, 882,000 mice and 144,060 rats were used in experiments in 2023, the university said.

"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," Khutoryanskiy said.

Despite efforts to adopt more ethical methods, animal testing remains central to how new brain drugs are developed.

Previous studies have already used planaria to explore epilepsy treatments and drug withdrawal, as the worms show primitive signs of addiction and withdrawal symptoms.

The latest findings strengthen the case for expanding their use, Khutoryanskiy said.

"It's good for science and it’s good for animal welfare," he said.