Study shows depression increases a person's risk of dementia.
Rush University Medical Center researchers analyzed the association between dementia and depression and found that those who were depressed were more likely to have the neurodegenerative disorder in the future. However, the team has not been able to determine whether depression is a factor that helps develop dementia or whether dementia causes people to be depressed.
Previous studies saw a correlation between the disorders and in 2003, researchers reviewed 23 studies of around 50,000 older people and reported that depressed adults were over twice as likely to have dementia and 65 percent more likely to have Alzheimer's. However, findings have only been about associations.
The researchers had to find out if both disorders develop from one underlying problem in the brain and if the relationship between the two has to do with dementia-related pathology. The study showed that the association is independent of brain changes related to dementia.
For the study, the researchers analyzed 1,764 participants aged an average of 77 years old from the Religious Orders Study and Rush Memory and Aging Project. The participants did not have any memory or thinking problems when the study started. Every year for about eight years, the participants were tested for depression symptoms including lack of appetite and loneliness. They also took tests on memory and thinking skills.
Around 50 percent of the participants experienced mild thinking and memory ability problems during the study period. These symptoms are often a precursor to Alzheimer's. Eighteen percent or 315 people developed dementia. 680 people died in the course of the study and the autopsies of 582 of them searched for brain damage signs. Depression accounted for around 4.4 percent of the difference in mental deterioration that is not attributed to damage related to dementia in the brain.
"These findings are exciting because they suggest depression truly is a risk factor for dementia, and if we can target and prevent or treat depression and causes of stress we may have the potential to help people maintain their thinking and memory abilities into old age," study author Robert Wilson PhD from Rush University Medical Center, Chicago said.
The study showed that people suffering from dementia were much more likely to suffer higher depression symptom levels before dementia but these people experienced a faster decrease in depression once dementia developed.
Scientists may find new depression treatments to decrease the dementia risk no matter how small. Mediation and sleeping longer hours are some of the activities that may calm the brain and improve cognitive health.
