A recent study from the University of Geneva (UNIGE) has revealed that the cerebellum, traditionally associated with motor functions, plays a significant role in the negative symptoms of schizophrenia by influencing the brain's reward system. The findings, published in Biological Psychiatry, suggest new possibilities for targeted and non-invasive treatments.
Schizophrenia affects about 1% of people worldwide and is often recognized for symptoms such as hallucinations and delusions. However, it also includes negative symptoms like apathy, reduced ability to feel pleasure, and social withdrawal. These symptoms are particularly challenging to treat.
Previous research has linked abnormalities in the brain's reward system—especially in the dopamine-producing ventral tegmental area (VTA)—to these negative symptoms. In individuals with schizophrenia, overactivity in the VTA may lead to a diminished sense of importance or salience, resulting in low motivation.
The UNIGE team, working with Geneva University Hospitals (HUG), followed 146 patients over three to nine months and analyzed an independent validation group. They observed a functional connection between the cerebellum and the VTA in schizophrenia patients.
"What is sometimes called our 'little brain' actually contains 50% of all our neurons. Although it was long considered to have a purely motor function, we are now discovering that it also plays important emotional and cognitive roles," said Indrit Bègue, assistant professor at UNIGE’s Laboratory of Neuroimaging and Translational Psychiatry and researcher at the Synapsy Centre for Neuroscience Research in Mental Health.
Jade Awada, doctoral student at UNIGE and first author of the study, explained: "We show that stronger cerebellar regulation of the reward system is associated with a reduction in negative symptoms — and conversely, weaker regulation with an increase in symptoms. This newly identified mechanism opens up promising avenues for targeted therapeutic interventions."
Unlike the VTA located deep within the brain, the cerebellum sits on its surface at the back of the skull. This position makes it more accessible for non-invasive treatments such as transcranial magnetic stimulation (TMS).
A randomized controlled trial funded by organizations including the Leenaards Foundation is underway at Campus Biotech to further investigate these findings. Results from this trial are expected by 2028.
