By Jane Elliott
Health reporter, BBC News
John says people do not believe his diagnosis
When John Crossley-Stanbury noticed a tremor in his little finger he ignored it.
At 19 he was a fit young man and he assumed the problem was simply a trapped nerve.
Two years later he went to see his GP who referred him to a neurologist. He got reassuring news. The specialist was convinced there was a benign reason for his problem.
But two years later, after a barrage of tests, he was told that he had Parkinson's Disease - an incurable and progressive neurological condition.
People with the condition have a shortage of the brain chemical dopamine, which controls connections between nerve cells, leading to symptoms such as tremors.
"My neurologist, quite rightly tested first for everything else it could possibly be," said the 26-year-old from Barnsley, South Yorkshire.
"But I think my age slowed down the diagnostic process. Everyone thinks it is an old person's disease, but it does affect young people.
"I was shocked by the diagnosis, but had begun to think it was something serious," he said.
John, who now has trouble walking and has suffered from depression and poor sleep, said it was important that people are also told there is hope.
"When they told me it was progressive and would get worse it was frightening. And to make it worse I'd done my own research on the internet and the only cases I could find were in the later stages.
Parkinson's disease attacks the part of the brain that controls our movements, it affects activities such as talking, walking, swallowing and writing
10,000 people are diagnosed with Parkinson's in the UK every year
One in 20 is under the age of 40
"They could not speak, some could not walk and were immobile."
And this is the image that wrongly sums up the disease in the eyes of the public.
John met with so much disbelief about his diagnosis that he took to carrying around his consultant's letter to account for his uncontrollable shaking.
"I have had people thinking I have been drinking or a druggie and I've had funny looks.
"To be honest I've done it myself to others. But since my diagnosis I have thought 'no' they could have something wrong with them."
He said that once he got over the shock of his diagnosis, he decided to be as positive as possible.
John has also taken on a new determination to get things done. "I'm creative," says John, who used to run his own publishing business, "but having Parkinson's has made me want to do more creative things more quickly - before I can't do them anymore".
John was a soldier for two years
He is now writing an autobiography.
But he says speaking publicly about his condition is vital to get a better understanding of the disease.
"The general public do not have that much knowledge about Parkinson's or its effect on people."
A recent survey by the charity Parkinson's UK confirmed this finding, showing that only 9% of the UK population realise that as many as one in 20 people with Parkinson's are diagnosed under the age of 40.
Dr Kieran Breen, director of research at the charity, said that although John was exceptionally young it was myth that only the elderly have the condition.
"People automatically identify Parkinson's with an older age group," he said.
"We are always trying to make people aware that there are younger people with the disease.
"It is difficult to diagnose in younger people, so it may not be obvious when they present at the age of 19 with symptoms.
"So sometimes it can take longer to diagnose."
Dr Breen said that even though the condition is incurable that there is medication to control symptoms.