The anti-psychotic drugs are known to be overprescribed in care homes

Some health trusts are failing to help drive down the use of "chemical cosh" drugs for dementia patients, a snapshot survey has found.

Anti-psychotic drugs, which are recommended in the short-term to calm down people who are agitated or violent, are known to be overprescribed, particularly in care homes.

In January, a three-year study published in The Lancet Neurology found people taking the drugs for long periods were twice as likely to die early as those not on them.

Government ministers are reviewing use of the drugs in dementia care but the report has not yet been published and is months past its due date.

A survey of 62 primary care trusts (PCTs) for GP newspaper found 57% were failing to offer services to help GPs cut prescribing of the drugs risperidone and olanzapine.

GPs have said they are forced to prescribe the drugs owing to a lack of alternative services for patients.

Half of PCTs also do not carry out audits recommended by the National Institute for Health and Clinical Excellence (Nice) to find those dementia patients who are suitable for treatment with acetyl-cholinesterase inhibitors, such as donepezil, rivastigmine and galantamine.

The drugs are not approved for use on the NHS in patients with early-stage Alzheimer's disease but can be used for those in the moderate stages.

Emma Bower, editor of GP, said: "Over the past year GP has been investigating some of the problems faced by GPs and their patients with dementia. We have found that many primary care trusts are failing to commission specialist services to support patients with dementia," she said. "This often leaves GPs with little choice but to prescribe anti-psychotics when patients become agitated and disturbed because there is no other support available."

A spokeswoman for the Department of Health said: "This is an important and complex issue, which can affect people with dementia in all care settings. That is why we have commissioned an independent review of antipsychotic drug use in people with dementia that we expect to publish next month."