Depression in dementia is common, up to 16% of people with Alzheimer’s disease develop depression but it is not known why it is more common in those living with Alzheimer’s than in older adults without dementia. Individuals with depression in dementia also appear to have different symptomatology with less symptoms of appetite reduction and thoughts of life not being worth living. Currently available anti-depressants are ineffective making the depression difficult to treat.
Alzheimer’s disease is a physical disease that affects the brain and, according to charity Alzheimer’s Society, who co-funded the research, 900,000 people in the UK have a form of dementia.
Researchers from Bristol’s Dementia Research Group wanted to investigate whether risk factors known to increase the risk of depression in adults without dementia, also increased the risk of depression in those with Alzheimer's, to identify possible new treatment targets.
Using data from three major dementia-focused cohorts, the team analysed depression ratings on 2,112 individuals with Alzheimer's and compared this with data from 1,380 participants with normal cognition.
Their results showed that risk factors for depression in Alzheimer's appear to differ to those for depression, supporting suggestions of a different pathological process, although a family or past history of depression was the strongest individual risk factor suggesting a possible genetic predisposition. Individuals with depression in Alzheimer’s were more likely than those with the disease who are not depressed to develop apathy and other non-memory symptoms of Alzheimer's disease.
'Characterization of depressive symptoms in dementia and examination of possible risk factors' by L Sinclair et al. in the Journal of Alzheimer's Disease [open access]