Additional patterns of symptoms, such as for example chronic depression, appear never to be linked, a report found.
Dutch researchers viewed various ways depression in old adults progressed as time passes and how this linked to any risk.
They concluded worsening depression may transmission the problem is taking hold.
The study, published in The Lancet Psychiatry, followed a lot more than 3,000 adults aged 55 and over residing in the Netherlands.
All had depression but zero symptoms of dementia in the beginning of the study.
Dr M Arfan Ikram of the Erasmus University INFIRMARY in Rotterdam said depressive symptoms that steadily increase over time look like a much better predictor of dementia later on in life than additional paths of depression.
“There are a variety of potential explanations, including that depression and dementia may both be symptoms of a common underlying cause, or that increasing depressive symptoms are about the starting end of a dementia continuum in older adults,” he said.
Just the group whose symptoms of depression increased as time passes were found to be at increased threat of dementia – on the subject of one in five of people (55 out of 255) in this group created dementia.
Other people who had symptoms that waxed and waned or stayed the same weren’t at increased risk.
For example, in those that experienced low but steady levels of depression, around 10% went on to develop dementia.
The precise nature of depression on dementia risk remains unknown.
They often times occur together, however the Dutch study is probably the first to check out different patterns of depression symptoms.
Dr Simone Reppermund from the Center for Healthy Mind Ageing at the University of New South Wales, Sydney, said more research were had a need to understand the link.
“A concentrate on lifestyle factors such as physical activity and internet sites, and biological risk elements such as for example vascular disease, neuroinflammation, high concentrations of tension hormones, and neuropathological adjustments, might bring fresh treatment and prevention strategies a stage closer,” she wrote in a linked editorial in the journal.
Depression varies greatly in one person to some other. Some encounter depressive symptoms only briefly, others possess remitting and relapsing depression plus some people are depressed at all times.
Dr Simon Ridley, director of study at Alzheimer’s Study UK, said anyone concerned about either condition should look for help.
“The findings recommend that low degrees of depression or fluctuating symptoms might not affect dementia risk but a worsening of symptoms in the over-55s could be an early on indicator of diseases like Alzheimer’s,” he said.
“It’s important to understand that just a relatively few of individuals experiencing symptoms of depression continued to develop dementia in this 11-year research, but anyone worried about either condition should speak to their GP.”