People who suffer from mild cognitive impairment (MCI) have an increased risk of converting to Alzheimer's disease within a few years, but a new study warns the risk increases significantly if they suffer from anxiety.

Research from scientists at Baycrest Health Sciences' Rotman Research Institute has shown clearly for the first time that anxiety symptoms in individuals diagnosed with MCI increase the risk of a speedier decline in cognitive functions -- independent of depression (another risk marker). For MCI patients with mild, moderate or severe anxiety, Alzheimer's risk increased by 33, 78 and 135 percent respectively.

The research team also found that MCI patients who had reported anxiety symptoms at any time over the follow-up period had greater rates of atrophy in the medial temporal lobe regions of the brain, which are essential for creating memories and which are implicated in Alzheimer's.89

"Our findings suggest that clinicians should routinely screen for anxiety in people who have memory problems because anxiety signals that these people are at greater risk for developing Alzheimer's," Linda Mah, principal investigator on the study, said in a statement.

Until now, anxiety as a potentially significant risk marker for Alzheimer's in people diagnosed with MCI has never been isolated for a longitudinal study to gain a clearer picture of just how damaging anxiety symptoms can be on cognition and brain structure over a period of time. There is a growing body of literature that has identified late-life depression as a significant risk marker for Alzheimer's. Anxiety has historically tended to be subsumed under the rubric of depression in psychiatry. Depression is routinely screened for in assessment and follow-up of memory clinic patients; anxiety is not routinely assessed.

For the study, researchers accessed data from the large population-based Alzheimer' Disease Neuroimaging Initiative to analyze anxiety, depression, cognitive and brain structural changes in 376 adults, aged 55 - 91, over a three-year period. Those changes were monitored every six months. All of the adults had a clinical diagnosis of amnestic MCI and a low score on the depression rating scale, indicating that anxiety symptoms were not part of clinical depression.

The findings are detailed in The American Journal of Geriatric Psychiatry.