Many younger people with the condition, aged as young as 39, have said they were handed information which showed pictures of pensioners and did not deal with the problems they faced, such as having to give up a job and still pay the mortgage.
To counter the problem, a new information pack including a DVD is being launched today which will be given to everyone diagnosed with early onset dementia.
Alex Murphy, services manager for Alzheimer Scotland, said: "You are in your fifties and you are thinking about retirement. You may be caring for an older relative, you may have children at school. The emotional, psychological and financial impact of early onset dementia can be tremendous."
NHS Health Scotland, the health promotion arm of the health service, and Alzheimer Scotland worked together on the materials which are being unveiled at a conference about the problem.
On the DVD patients describe the first symptoms they noticed, among them leaving on the iron, being confused about arrangements or forgetting to feed the cat.
Dr Gary Stevenson, consultant psychiatrist in NHS Fife, said early symptoms were often laughed off as "having a senile moment".
He said: "Children will laugh because yet again mum has burned the dinner, but although initially it is funny it becomes more serious.
"The families and the individual become frustrated and they look around for answers."
While Alzheimer's disease is still the most common form of dementia in younger adults, they are more prone to the rarer types which cause behaviour change rather than memory loss.
Dr Stevenson said that, with GPs hardly ever seeing the condition, it was not uncommon for it to be three or four years before patients were accurately diagnosed.
The average survival time from the point when symptoms show is five to seven years - and it can be more aggressive in the young.
Mr Stevenson said patients will increasingly become reliant on partners to manage daily life and may end up in care homes where the average age is 85.
While early onset dementia can be inherited, little is known about why some people are prone to the problem.
The new leaflet gives tips on telling others about the diagnosis, including employers and children. It also advises patients about their rights at work and how they could try to re-organise their workload to make it more manageable. On the DVD patients talk about what could have helped them at the time of diagnosis.
Dr Stevenson advised people not to ignore persistent concerns about forgetfulness.
Fiona Borrowman, programme manager at NHS Health Scotland, said it was important people took memory problems seriously.
However, she added they should not worry unnecessarily as memory issues could be triggered by a range of causes which were not related to dementia.