MedWire News: Patients with schizophrenia are significantly less dexterous than those without the mental health condition, Japanese researchers have found.

Dr Katsuki Nakamura, from the National Center of Neurology and Psychiatry in Tokyo, and team suggest that poor motor function - the ability to control muscles and movements - could be an indicator of schizophrenia development in people at high risk of the condition.

The researchers studied 27 patients with schizophrenia and 49 volunteers without the mental health disorder.

All the participants underwent a variety of tests to assess their 'motor dexterity', including a test in which they were asked to rotate each finger clockwise and counterclockwise, while keeping their other fingers in a fixed position.

The participants also underwent tests to assess their memory and other 'cognitive' abilities.

The team found that the schizophrenia patients performed significantly worse on the dexterity tests than the mentally healthy volunteers, even after accounting for the use of antipsychotic drugs.

Indeed, out of the highest possible dexterity score of 25 on the finger test, the schizophrenia patients scored 13 compared with 22 among the mentally healthy participants.

The schizophrenia patients also performed significantly worse on the cognitive tests than their mentally healthy counterparts.

"We demonstrated profound impairment in motor dexterity as well as cognitive impairment in chronic schizophrenia," the researchers write in the journal Psychiatry Research.

They conclude: "Impaired motor dexterity is a major characteristic of schizophrenia."