Around 6,300 people in the UK who believe they are suffering from Parkinson's disease could have been wrongly diagnosed, a new study has claimed.
Researchers in Scotland, who assessed patients on anti-Parkinson's medication, found that five per cent had little more than stiffness or hand tremors.
A report published in the Movement Disorders journal warned that millions of pounds was being wasted on unnecessary drugs each year.
While the wrongly prescribed medication was not thought to have any adverse side effects, patients were subjected to years of anxiety.
Dr Keiran Breen, one of the authors of the report said Parkinson's was a notoriously difficult disease to diagnose accurately in its early stages, but recommended all suspected sufferers should be referred to specialists regularly.
He said: "No two people with Parkinson's disease will have the same diagnosis. The three main characteristics are tremors, slowness of movement and stiffness, but not everyone will have all three symptoms. The patients should be referred to neurologists with more expertise and they will make a much more accurate diagnosis."
There are around 120,000 sufferers in the UK but during the study more than five per cent were found to have been misdiagnosed.
Dr Breen said: "We didn't find evidence that taking drugs caused harm to the patients without Parkinson's but it could mean people were denied the correct drugs to improve their actual condition."