Anti-depressant Celexa offers ray of hope in preventing Alzheimer's

Research shows a common antidepressant may cut production of one of the chief suspects behind Alzheimer's, a new avenue in the hunt for drugs to prevent the devastating brain disease.

It's far too early for anyone worried about dementia to try the drug citalopram, which sells as the brand Celexa - and comes with side effects.

"This is not the great new hope. This is a small step," cautioned Dr Yvette Sheline of the University of Pennsylvania in the US, who is leading the research with Dr John Cirrito of Washington University in St Louis.

Alzheimer's is characterised by sticky plaques that form in patients' brains 10 to 15 years before the first memory symptoms are noticed. Scientists have tried treatments to clear away those plaques, made of a protein named beta-amyloid that somehow goes awry and starts clumping together, with no success.

The study is a somewhat different approach, beginning to explore if it's possible to slow the plaque from building up by altering the production of amyloid.

First, researchers gave citalopram to older mice with Alzheimer's-like brain damage. Their existing plaques didn't go away but quit growing - and much fewer new plaques formed compared to mice given sugar water.