A new study indicated that depression may put an individual to a risk of dementia. The study conducted at the University of Massachusetts in Worcester, and Boston University in the US was a cohort study and aimed to determine a possible relation between depression and dementia.

The study included participants from the Framingham Heart study; a long-running cohort study started in 1948 to look into risk factors for heart disease. This specific study was commenced in 1990 and 949 participants who were free of dementia were included in the study. All participants were looked for any symptoms of depression with use of depression scale (range 0-60), with higher score indicating larger depressive symptoms. A score of 16 and above was used to define depression. From 949 participants, 125 found to have depression from which 39 were taking anti-depressant medicines.

The investigator followed up the participants for 17 years and participants that developed dementia were discovered utilizing regular testing every two years. A questionnaire form, with other findings from physicians and their family, was used to test memory deterioration. Participants with likely dementia features had extra neurological tests and were reexamined by medical specialist. Diagnosis of dementia were made utilizing a formalized diagnostic tool, and further review for Alzheimer’s disease was made using laid down criteria. 

During the period of follow up, 164 participants had dementia and 136 of these developed Alzheimer's disease. 21.6% of participants evaluated as depressed at the beginning of the research developed dementia, compared to 16.6% of non-depressed participants. This suggested persons with depression had 72% increased risk of dementia. These findings supported former studies conducted in this area. 

This study contributes to further evidence that there is a strong link between depression in older persons and risk of developing dementia. Nevertheless, the grounds for the discovered connection are not totally clear, and additional investigations would be required to show if this was a cause-and-effect association, or if there was a similar disease course or causative factor inherent in both conditions.