Feb. 15 (UPI) -- Individuals who are not aware of their own memory problems are nearly three times more likely to develop some form of dementia, including Alzheimer's disease, within two years, according to research at McGill University in Montreal.
In a study published Thursday in the journal Neurology, a team from McGill's Translational Neuroimaging Laboratory studied individuals who experience memory lapses. The study was led by Dr. Pedro Rosa-Neto, co-senior author of the study and clinician scientist and director of the McGill Center for Studies in Aging.
"This study could provide clinicians with insights regarding clinical progression to dementia," Rosa-Neto said in a press release.
Anosognosia, frequently referred to as a lack of insight, is a common symptom of certain mental illnesses -- including 50 percent of people with schizophrenia and 40 percent of people with bipolar disorder -- according to the Treatment Advocacy Center. The condition is also often linked to Alzheimer's disease, researchers say.
Patients, the Center said, appear to be rational in refusing treatment and totally unaware of their condition, regardless of how obvious it is to people around them.
Joseph Therriault, a master's student in McGill's Integrated Program in Neuroscience and lead author of the paper, studied data from the Alzheimer's Disease Neuroimaging Initiative, a global research effort in which patients complete a variety of imaging and clinical assessments.
He studied 450 patients with mild memory deficits but who were still able to take care of themselves. Close relatives of the participants were also asked to fill out similar surveys.
If a patient reported no cognitive problems but the family member reported significant difficulties, the person was determined to have poor awareness of illness. Then researchers compared the poor awareness group to the ones with no awareness problems.
They found those suffering from anosognosia had impaired brain metabolic function and higher rates of amyloid deposition. This protein builds up in the brains of Alzheimer's disease patients.
"This highlights the importance of assessing awareness of cognitive decline in the clinical evaluation and management of individuals with amnestic mild cognitive impairment," researchers wrote in the paper.
In a followup study two years later, patients unaware of their memory problems were found to be more likely to have developed dementia regardless of genetic risk, age, gender and education. The researchers say they found this increased progression to dementia was similar to increased brain metabolic dysfunction in regions vulnerable to Alzheimer's disease.
"This has practical applications for clinicians: people with mild memory complaints should have an assessment that takes into account information gathered from reliable informants, such as family members or close friends," said Dr. Serge Gauthier, co-senior author of the paper and professor of Neurology & Neurosurgery, Psychiatry and Medicine at McGill.
University scientists plan to further explore how awareness of illness changes across the full spectrum of Alzheimer's disease.