It would be an early sign of psychosis

NEW YORK (HealthDay News)—“Hang on” may be a truer expression for holding on to your sanity than previously thought, according to a new study.

A loss of grip strength may be an early sign of psychosis, researchers report in the American Journal of Psychiatry. People recently diagnosed with psychosis have weaker grip strength compared to people in good mental and physical health.

“Poor grip strength has been associated with many negative outcomes in a variety of people: lower well-being, higher mortality risk, poor daily functioning, and poor quality of life,” said lead researcher Alexandra Moussa-Tooks, a professor of psychological and brain sciences at Indiana University.

“Grip strength seems to capture that things are not going well, but it has not been well studied in relation to brain function or early psychosis.”

Psychosis often begins with changes in the way people move their bodies, before progressing to delusions such as paranoia or hallucinations, experts said.

In the new study, scientists compared 89 people diagnosed with psychosis in the past five years with 51 healthy individuals.

People with psychosis had lower grip strength and scored worse on well-being assessments compared to the control group.

Brain scans showed that these problems were linked to three key brain regions connected to the default mode network, a brain system that activates when people are daydreaming or not focused on any particular task.

Greater grip strength and greater well-being were associated with increased connectivity between three brain regions: the anterior cingulate cortex, the sensorimotor cortex, and the cerebellum.

These results suggest that the decline in grip strength may reflect changes in what researchers call “resting-state functional connectivity,” a measure of brain network function.

“Our findings are particularly exciting because they identify potential brain targets for new treatments for psychosis,” said Dr. Heather Burrell Ward, assistant professor of psychiatry and behavioral sciences at Vanderbilt University Medical Center in Nashville, Tennessee.

For example, magnetic stimulation could be used to increase that connectivity. Another approach would involve physical exercise, which would indirectly strengthen brain networks.

“If psychosis is a house on fire, symptoms like delusions and hallucinations are the smoke,” Moussa-Tooks explained. “In a fire, you don't attack the smoke, but the fire and its source. And yet, that's not currently how we approach the treatment of psychosis.”

He said motor disturbances help investigators identify where the fire may have started and spread.

"They are more fundamental in the sense that they are easier to link to different disorders in the brain," he added.

Grip strength could also be used as an early screening tool for psychosis or other types of mental illness. “Grip strength and other motor functions are easily assessed and more easily interpreted than the complex tasks often used to study psychosis,” Moussa-Tooks said.

“Our work is demonstrating that these seemingly simple metrics can help us understand alterations not only in the motor system, but also in the complex brain systems that give rise to the complex symptoms we see in psychosis.”

At a glance

Treatments

The findings on grip strength identify potential brain targets for new treatments for psychosis. Magnetic stimulation could be used to increase brain connectivity, and another approach would involve physical exercise.