A drug containing the sleep hormone melatonin is to be tested in Scotland to find out if it helps reduce the effects of dementia.
Glasgow-based firm, CPS Research, aims to recruit 50 people with Alzheimer's disease for the clinical trial of the drug, Circadin.
Alzheimer's patients do not have normal melatonin levels and the study will gauge the effects of adding it.
Initial findings suggest it may lead to improved well being during the day.
The most common cause of dementia is Alzheimer's disease - which causes the death of brain cells - but other conditions that affect the brain can also cause it.
Dr Gordon Crawford, of CPS Research, said: "Dementia is a shattering condition for patients, their families and friends. By reducing the symptoms of the illness, it is hoped that both patients and their carers can enjoy a better quality of life and manage the condition more effectively.
"In our groundwork for this project we investigated a slow-release version of the natural compound melatonin. Our findings suggested that the participants functioned better during the day - possibly due to a better quality sleep pattern."
Dr Crawford said that melatonin does not currently exist as a treatment for dementia but was registered in Europe and the UK for use with elderly patients with sleeping difficulties.
He said: "It has proven to be remarkably safe and virtually free from side effects. We are exploring whether its use as an add-on treatment for dementia could transform the lives of patients and their carers.
"With the help of volunteers from Scotland we aim to establish whether adding melatonin to current treatments could provide a major advance in dementia management."
Any patient who has been diagnosed with Alzheimer's and is currently receiving treatment could be eligible to take part in the trial, called "Melatonin in Alzheimer's Disease Project".
Since it is based in the west of Scotland, only patients who can travel there will be considered.
Dr Crawford added: "What we do know is that patients who have Alzheimer's disease do not produce melatonin like healthy people. The study aims to see how adding melatonin affects them.
"There's a small study with melatonin that suggests there might be some benefit but it hasn't been studied in any detail. This will be the first time it has been studied in a reasonable number of patients."