Tiny worms could change how we test mental health drugs

A new wave of mental health research may come from an unexpected source – tiny pond-dwelling worms. While they lack the complexity of mammalian brains, these creatures share surprising similarities in how they respond to certain drugs.

Scientists are now exploring whether these simple animals could take on a big role in developing treatments for serious mental illnesses, all while sparing countless mice and rats from laboratory testing.

Worms aid mental health research

Scientists from the University of Reading have discovered that harmless flatworms called planaria could help develop treatments for conditions like schizophrenia.

These small creatures respond to psychiatric medicines in ways similar to mice and rats. When given haloperidol, a drug used for mental health conditions, the worms became far less active, much like rodents do.

Past research has used planaria to explore epilepsy treatments and drug addiction, as they can show withdrawal symptoms.

The new study suggests the worms could be used to test medicines for schizophrenia and hallucinations. A 2024 study found that one in 69 UK adults uses anti-psychotic medication long-term.

“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,” noted Professor Vitaliy Khutoryanskiy, who led the study.

“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.”

Replacing lab rodents

Haloperidol works by calming overactive brain activity in people whose thoughts are racing or confused. Scientists often use animals, but now also study worms, to see how this drug affects the brain and to design better mental health treatments.

UK government data shows that in 2023, 882,000 mice and 144,060 rats were used in research. A 2016 study found that rodent use in neuroscience had increased from 20% in the 1980s to over 50% by the 2010s.

Even with growing efforts to make research more ethical, rodents remain the main test subjects. Planaria could reduce their numbers significantly.

The research explored how cyclodextrins – ring-shaped sugar molecules – can change the way haloperidol behaves in water. Types like hydroxypropyl-β-cyclodextrin and methyl-β-cyclodextrin boosted haloperidol’s solubility up to nearly 20 times compared to its natural level.

This works because cyclodextrins can trap haloperidol molecules inside their cavities. However, when trapped, the drug entered the worms less easily, showing that strong binding can limit delivery.

Sugars change drug behavior

Analyses confirmed that haloperidol and these cyclodextrins form stable 1:1 inclusion complexes in worms.

Advanced methods like nuclear magnetic resonance and thermal studies revealed that one aromatic ring of haloperidol sits inside the sugar ring’s cavity, offering insights for mental health research.

These complexes exist in an amorphous state, meaning the drug loses its crystal form. While this can help with dissolving the drug, it may also affect how quickly it becomes available in living systems.

Impact on mobility tests

The study measured how the worms moved in different solutions. Pure haloperidol reduced their mobility in a dose-dependent way, mimicking the catalepsy seen in mammals.

Cyclodextrin complexes caused a smaller drop in movement, likely because the drug was held too tightly. Interestingly, pure cyclodextrins also slowed the worms slightly.

Worms teach mental health science

The findings from this research have already made their way into the classroom at the University of Reading, influencing how future scientists are trained.

In undergraduate pharmacology courses, students are now introduced to the effects of haloperidol on planaria as part of their practical learning.

By observing how these simple organisms respond to the drug, students gain a deeper understanding of both the medicine’s action and the broader principles of neuropharmacology.

This early exposure to innovative and ethical research methods offers more than just technical knowledge. It encourages young scientists to think critically about alternatives to traditional animal testing, showing them that valuable results can come from models that reduce harm to higher animals.

Such hands-on experience not only builds practical skills but also shapes attitudes, potentially inspiring the next generation to develop humane, efficient, and impactful approaches to studying treatments for mental health conditions.

The study is published in the journal Pharmaceutical Research.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–