A new survey has found that 31 per cent of people would not know where to get support after being diagnosed with dementia.
The Alzheimer's Society poll, conducted by YouGov, also found that 14 per cent would want support but would not have anybody to turn to.
As a result, 74 per cent would be frightened and 55 per cent would feel depressed.
The poll was designed to raise awareness of the disease and encourage people to "remember the person" during Dementia Awareness Week (July 4th - 10th).
Acting chief executive of the charity Ruth Sutherland said it was "terrible" that people do not know how to get the help they need to deal with such a serious condition.
She added: "A million people will develop the condition in the next ten years.
"We need better awareness and information so that a diagnosis of dementia is not such a frightening experience."
According to the Department of Health, around 600,000 people in the UK currently live with dementia, with younger people accounting for some 17,000 cases.
Read more about Barchester's dementia care homes.