Photo for representation: iStock
Photo for representation: iStock

PTSD reduces cerebellum volume: New study offers targeted treatment approach

Reductions pronounced for particular subregions of cerebellum; more research needed to understand how genetic predisposition, environment leads to PTSD, authors say
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People who have Post-traumatic Stress Disorder (PTSD) can have considerable reductions in both grey and white matter volume in their cerebellum, a new study identified. This may impact their cognitive abilities as well as emotional responses, among other things, the researchers said

The study analysed data from a vast cohort of 4,215 adults, including 1,642 individuals diagnosed with PTSD and 2,573 healthy controls from 40 different locations. The report published in Nature’s Molecular Psychiatry journal is significant because it focuses on the cerebellum, a brain region traditionally associated with motor control, but now increasingly recognised for its role in higher cognitive and emotional functions.

Utilising advanced deep-learning techniques for cerebellar parcellation, the researchers assessed the volumes of the entire cerebellum and its 28 subregions. Their findings showed that PTSD is linked with considerable reductions in both grey and white matter volumes in the cerebellum. This reduction was particularly notable in specific subregions, including the posterior lobe, vermis, flocculonodular lobe and the corpus medullare.

“PTSD is incredibly burdensome at both the individual and societal level, causing profound distress, functional impairment, and staggering treatment costs,” the authors of the study highlighted.

The findings have multiple implications. First, it challenges the traditional understanding of PTSD as solely a disorder of the brain’s emotion-processing centres. The cerebellum’s involvement suggests a more complex brain network disruption in PTSD, one that includes regions responsible for integrating cognitive and emotional responses. 

This is in addition to the impact on a person’s vestibulomotor functions like the movement of eyes, head and balance of the body that are known to be controlled by the cerebellum. 

The detailed analysis showed that individuals with PTSD had smaller total cerebellum volumes, with marked reductions in lobule VIIB and crus II of the posterior lobe, lobules VI and VIII in the vermis, lobule X in the flocculonodular lobe and the corpus medullare. 

The study also showed that cerebellar volume changes correlate with the intensity of the PTSD experience, offering a potential biomarker for assessing the condition’s severity.

This research helps in understanding the pathophysiology of PTSD. By pinpointing specific cerebellar regions affected by the disorder, it paves the way for developing targeted therapeutic strategies that address these brain changes. 

Traditional treatments for PTSD primarily focus on psychological and pharmacological approaches targeting the brain’s emotion and memory centres. The involvement of the cerebellum may lead to innovative treatments that offer a more holistic approach to managing the condition.

However, the researchers acknowledged that while their findings are significant, they represent a piece of a larger puzzle. PTSD is a complex disorder with a myriad of contributing factors, including genetic predisposition, environmental triggers and individual psychological makeup. The study underscores the need for further research to understand how these factors interact with the observed cerebellar volume changes.

For instance, the impact of exposure to trauma that doesn’t lead to PTSD must be studied further, the researchers noted. “The small sample of trauma-naïve subjects precluded us from assessing whether there are cerebellar volume differences related to trauma exposure (not just PTSD), and future work to examine this question will be valuable.”

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