Summary: Psychosis may start not with hallucinations, but with subtle motor changes like reduced grip strength. A new study reveals that lower grip strength in people with early psychosis is linked to altered brain connectivity, particularly in networks that govern both movement and cognition.
These changes affect regions like the anterior cingulate cortex, sensorimotor cortex, and cerebellum, offering a more accessible way to detect and understand psychosis. The findings open the door to new interventions, from brain stimulation to physical training, that may strengthen these neural pathways and improve mental health outcomes.
Key Facts:
- Motor Clues: Poor grip strength in early psychosis links to reduced brain connectivity.
- Brain Targets: Disrupted communication in the default mode network may underlie both movement and mental symptoms.
- New Interventions: Treatments like TMS or motor training could boost brain function and well-being.
Source: Indiana University
Psychosis often begins not with characteristic disturbances of the mind – delusions like paranoia or hallucinations – but with disturbances in the way we move our body.
For researchers like Indiana University Assistant Professor Alexandra Moussa-Tooks in the Department of Psychological and Brain Sciences, these motor disturbances offer critical insights into the condition of psychosis itself.
In a new study published on June 25 in the American Journal of Psychiatry, senior-author Moussa-Tooks and first-author Heather Burrell Ward, assistant professor of psychiatry and behavioral sciences at Vanderbilt University Medical Center, explore one such motor ability – grip strength – to uncover the mechanisms linking motor disturbances to psychosis.
As Moussa-Tooks explains: “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.
“Grip strength seems to capture that things are not going well. But it hasn’t been well studied in relation to brain function or early psychosis. Our study looks at how grip strength may be an important sign of brain and psychological health in early psychosis.”
The study is the first to suggest that grip strength and overall well-being share common patterns of brain connectivity. It shows that impairment in grip strength and well-being may reflect alterations in what researchers call “resting-state functional connectivity,” a measure of brain network function that may be key to understanding psychosis.
Through a novel neuroimaging analysis, Moussa-Tooks and her collaborators demonstrate that brain networks with important roles in both motor and cognitive function play key roles in gripping ability and mental well-being. Their findings lay the groundwork for interventions aimed at improving functioning and wellness in early psychosis.
A unifying brain circuit explanation
The study’s data came from the Human Connectome Project for Early Psychosis, a large initiative conducted from 2016 to 2020 across multiple sites, among them the IU School of Medicine. It included 89 individuals in the first five years of psychotic illness and 51 healthy controls for whom age- or medication-related motor decline could be ruled out.
The analysis confirmed that participants with early psychosis had lower grip strength and well-being scores than healthy controls. These metrics related to three key brain regions —the anterior cingulate cortex, sensorimotor cortex, and cerebellum— each of which were shown to be connected to the default mode network.
Higher grip strength and greater well-being correlated with greater connectivity between these regions and the default mode network.
Identifying brain targets for new treatments
“Our findings are particularly exciting because they identify potential brain targets for new treatments for psychosis,” Ward said.
For example, both researchers see enormous potential in transcranial magnetic stimulation. If in psychosis there is poor communication within the default mode network, TMS is a non-invasive tool that can be used to directly increase that connectivity. Motor training, like exercise, to strengthen brain networks indirectly can offer another promising strategy.
“Grip strength and other motor functions,” Moussa-Tooks explains, “are easily assessed and more readily interpretable than complex tasks often used to study psychosis.
“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 that give rise to the complex symptoms we see in psychosis.”
Consider the following analogy, she suggests: “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. And yet, currently that’s not how we approach treatment for psychosis.
“Motor disturbances help us get closer to identifying where the fire may have started and spread. They are more fundamental in the sense that they’re easier to link to different disturbances in the brain.”
With this new study researchers are getting closer to the fire. By drawing a line between motor function and mental health – from grip strength and well-being to patterns of brain connectivity with a key role in psychosis – they are mapping out new paths for understanding and treating an elusive disorder.
About this psychosis research news
Author: Liz Rosdeitcher
Source: Indiana University
Contact: Liz Rosdeitcher – Indiana University
Image: The image is credited to Neuroscience News
Original Research: Closed access.
“Grip Strength as a Marker of Resting-State Network Integrity and Well-Being in Early Psychosis” by Alexandra Moussa-Tooks et al. American Journal of Psychiatry
Abstract
Grip Strength as a Marker of Resting-State Network Integrity and Well-Being in Early Psychosis
Objective:
Psychomotor function is a critical marker of risk and outcome of psychosis. Grip strength is one aspect of psychomotor function that is known to be linked to structural neural integrity and well-being.
This study sought to determine whether grip strength is a marker of alterations in resting-state connectivity and well-being in psychotic disorders in order to further clarify the mechanisms by which psychosis phenomenology is related to psychomotor processes.
Methods:
The authors analyzed resting-state functional MRI and grip strength in 89 individuals with early psychosis and 51 control subjects without psychiatric disorders from the Human Connectome Project for Early Psychosis. Participants ranged in age from 16 to 35 years.
Using multivariate pattern analysis of whole-connectome data, the authors identified brain correlates of grip strength and then replicated this analysis using the NIH Toolbox well-being measures and the Global Assessment of Functioning Scale (GAF).
Results:
The psychosis group exhibited reduced grip strength, well-being, and GAF scores compared to the control group. Grip strength was linked to resting-state connectivity in the sensorimotor cortex, anterior cingulate cortex, and cerebellum. Connectivity correlated with the default mode network (DMN) (rsensorimotor=0.22, rcingulate=0.30, rcerebellum=0.24).
When the analysis was repeated for GAF and well-being, overlapping regions in the sensorimotor cortex and cerebellum were connected to the DMN and related to GAF (rsensorimotor=0.17, rcerebellum=0.28) and well-being (rsensorimotor=0.16, rcerebellum=0.16). Relationships were driven by the psychosis group for cerebellum and cingulate nodes.
Conclusions:
Data-driven, connectome-wide analysis identified shared brain correlates of grip strength, overall function, and well-being in a sample of young adults with psychosis and healthy control subjects.
This suggests that grip strength may be a marker of DMN connectivity, which may in turn be an important marker of overall health, even in young adult populations.
