Grip strength and patterns of brain connectivity may offer early indicators of psychosis, according to researchers exploring new avenues for detection and treatment.
The study found that people in the early stages of psychosis had weaker grip strength and lower well-being scores than healthy individuals, with both measures linked to changes in how brain networks function.
Motor changes can occur before classic symptoms of psychosis—such as hallucinations or delusions (false beliefs, often involving paranoia)—and may act as an early warning.
Alexandra Moussa-Tooks is assistant professor in the department of psychological and brain sciences at Indiana University.
She said: “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.”
This is the first study to show that grip strength and well-being share common patterns of brain connectivity—how regions of the brain communicate with each other.
Researchers used a neuroimaging method known as resting-state functional connectivity, which examines brain network activity when a person is not performing a task.
Data came from the Human Connectome Project for Early Psychosis, conducted between 2016 and 2020 across multiple sites.
The study included 89 individuals within the first five years of psychotic illness and 51 healthy controls.
Using a novel neuroimaging analysis, the team identified three key brain regions—the anterior cingulate cortex, the sensorimotor cortex, and the cerebellum—that were connected to the default mode network, a brain system active during rest and involved in self-focused thought.
Higher grip strength and greater well-being were both linked to stronger connectivity between these areas and the default mode network.
Heather Burrell Ward is assistant professor of psychiatry and behavioural sciences at Vanderbilt University Medical Center.
Ward said: “Our findings are particularly exciting because they identify potential brain targets for new treatments for psychosis.”
The team highlighted the potential of transcranial magnetic stimulation (TMS)—a non-invasive method using magnetic fields to stimulate brain activity—to improve connectivity in the default mode network.
They also suggested that motor training and physical exercise could help indirectly strengthen relevant brain circuits.
Moussa-Tooks said: “Grip strength and other motor functions 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 understand disturbances not only in the motor system, but across complex brain systems that give rise to the complex symptoms we see in psychosis.”
She added: “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.”
