Grip Strength Reveals Brain Changes in Early Psychosis

A simple squeeze of the hand might reveal profound changes happening in the brain during early psychosis.

New research shows that grip strength—long considered a basic measure of physical health—actually reflects the integrity of critical brain networks that govern both movement and mental well-being. This discovery offers researchers a surprisingly accessible window into one of psychiatry’s most complex conditions.

The study, published in the American Journal of Psychiatry, examined 89 individuals in their first five years of psychotic illness alongside 51 healthy controls. Using advanced brain imaging, researchers found that weaker grip strength correlated with disrupted connectivity in key brain regions, particularly within the default mode network—a circuit crucial for self-awareness and cognitive function.

Beyond the Obvious Symptoms

Psychosis typically brings to mind dramatic symptoms like delusions and hallucinations. But researchers are increasingly recognizing that motor disturbances often appear first, offering early warning signs that could improve diagnosis and treatment.

“Poor grip strength has been associated with many negative outcomes in a variety of people: lower well-being, higher risk of mortality, poor day-to-day functioning, poor quality of life,” explained Indiana University Assistant Professor Alexandra Moussa-Tooks, the study’s senior author. “Grip strength seems to capture that things are not going well.”

The research team used data from the Human Connectome Project for Early Psychosis, a multi-site initiative that ran from 2016 to 2020. Participants ranged from 16 to 35 years old, allowing researchers to examine psychosis in its earliest stages before age-related decline could confound results.

Mapping Brain Networks

Through sophisticated neuroimaging analysis, the team identified three brain regions where grip strength correlated with network connectivity:

• Sensorimotor cortex: Controls voluntary movement and sensory processing
• Anterior cingulate cortex: Integrates emotion, attention, and decision-making
• Cerebellum: Coordinates movement and supports cognitive functions

All three regions showed connections to the default mode network, with stronger connectivity correlating to better grip strength and overall well-being. The correlation coefficients ranged from 0.16 to 0.30, indicating meaningful relationships between brain function and physical performance.

When researchers examined overall functioning and well-being measures, they found overlapping patterns in the sensorimotor cortex and cerebellum, suggesting these brain networks serve dual roles in both physical and mental health.

A Fire and Smoke Analogy

Moussa-Tooks offers a compelling metaphor for understanding these findings: “If psychosis is a house on fire, symptoms such as delusions and hallucinations are the smoke. In a fire you don’t target the smoke, you target the fire and its source.”

Motor disturbances like reduced grip strength may help researchers locate that fire’s origin. Unlike complex cognitive tasks traditionally used to study psychosis, grip strength provides a straightforward, easily measured indicator of brain network integrity.

“Grip strength and other motor functions are easily assessed and more readily interpretable than complex tasks often used to study psychosis,” Moussa-Tooks noted. “Our work is showing that these seemingly simple metrics can help us understanding disturbances not only in the motor system, but across complex brain systems.”

Treatment Implications

The findings point toward potential therapeutic targets that could address psychosis at its neurological roots rather than just managing symptoms. First author Heather Burrell Ward of Vanderbilt University Medical Center emphasized the treatment possibilities.

“Our findings are particularly exciting because they identify potential brain targets for new treatments for psychosis,” Ward said. The researchers see promise in transcranial magnetic stimulation (TMS), a non-invasive technique that could potentially strengthen connectivity within the default mode network.

Motor training and exercise represent another avenue, offering indirect ways to strengthen brain networks through physical activity. This approach could complement existing treatments by targeting the underlying neural circuits rather than just alleviating symptoms.

Closer to the Source

This research represents a shift toward understanding psychosis through its earliest manifestations. By connecting a simple physical measure to complex brain networks, researchers are developing tools that could identify at-risk individuals before severe symptoms emerge.

The study’s data-driven approach avoided the limitations of hypothesis-driven research, allowing patterns to emerge naturally from the brain connectivity data. This methodology revealed that grip strength serves as a surprisingly sensitive marker of neural network health in young adults.

As researchers continue mapping the relationship between motor function and mental health, they’re getting closer to understanding psychosis at its source—potentially transforming how we detect, understand, and treat this challenging condition.