Doctors in some areas in England are still "inappropriately over-prescribing" anti-psychotic drugs to dementia patients, campaigners said.
In the north west 13% of dementia patients are being prescribed the drugs - which are designed to treat conditions such as schizophrenia and can have serious side effects for dementia sufferers - compared to just 2% in London.
Do anti-psychotic drugs do more harm than good?
Doctors in Yorkshire and the Humber gave 9% of dementia patients the medication while in the north east of England just 2.5% of sufferers were prescribed such drugs, according to data from the Health and Social Care Information Centre (HSCIC).
The Mental Health Foundation said it was "concerned" that the research reveals varying levels of prescriptions around England. Toby Williamson, head of development and later life at the charity said: "This strongly indicates that some areas are still inappropriately over-prescribing."
SEE ALSO:
Unnecessary use of anti-psychotic drugs is killing 1,800 patients prematurely every year, according to the Department of Health.
But overall, the HSCIC figures show that the number of patients being prescribed the drugs has fallen sharply in recent years.
Researchers, who examined data from 197,000 people with dementia, found that in 2011, an average of 6.8% of dementia patients in England were prescribed anti-psychotics compared to 17% in 2006.
HSCIC chief executive Tim Straughan said: "This audit breaks new ground in examining prescribing patterns for dementia patients and highlights areas that GPs and other practices who want to deliver the best possible care need to focus on.
ALSO READ:
"It is encouraging that prescribing of anti-psychotic drugs is falling.
"However, it is clear that the picture nationally is mixed and that everyone involved in the care of those with dementia needs to look carefully at how they compare with others in their practices."
Mr Williamson added: "We welcome the fall in prescriptions of anti-psychotic drugs for people with dementia but we are concerned about the wide regional variations.
"Other interventions can be used to reduce distress and agitation among people with dementia."
Care services Minister Paul Burstow said: "More than halving the number of people with dementia receiving anti-psychotics marks a huge change in the right direction. It means tens of thousands of people will not be robbed of part of their lives to needless prescribing.
"But we can and must go further. That is why we are developing a risk assessment tool to help doctors use the drugs safely and appropriately. I have also ordered the rerun of this audit to keep tabs on the action that is being taken to tackle the unacceptable regional variation that we have exposed.
"The momentum is building and I am determined to take all necessary steps to protect people from unnecessary prescribing."
Alzheimer's Society chief executive Jeremy Hughes added: "This momentous achievement is not just about statistics, it is about the lives of tens of thousands of people with dementia.
"However, there are still tens of thousands more people - both diagnosed and undiagnosed - having their lives put at risk by these drugs and some parts of the country are failing to reach the mark.
"Now is the time to move from fourth gear to fifth to ensure everyone's prescriptions are reviewed and that only those people who benefit are kept on anti-psychotics. They must only be a last resort."