Depression in later life could signal dementia risk

Chronic stress and anxiety may also 'damage' the brain

Portrait of a very sad and depressed older woman suffering from stress or a strong headache isolated on black

Depression in later life could be a sign of brain changes that can make a person more prone to developing dementia, say researchers. And if your older and your depression worsens steadily over time, it's even more important to see your GP.

See also: Eight hidden signs of dementia

See also: People 'frequently misdiagnosed with common types of dementia'

Link between depression and dementia
Dementia is more common in those who become depressed in middle age or later in life than among those who aren't depressed, according to research published in the Archives of General Psychiatry.

In fact, people with late-life depression have double the risk for Alzheimer's disease, while those whose depression begins in midlife are three times at risk for vascular dementia (caused by poor blood flow in the brain).

Depression that steadily increases
Depression which gets steadily worse over time is a particular risk for those in later life and could be an early indicator of dementia, say scientists. Dutch researchers looked at different ways depression in older adults progressed and believe that increasing depression may signal the condition is taking hold.

Dr M Arfan Ikram of the Erasmus University Medical Center in Rotterdam said: "There are a number of potential explanations, including that depression and dementia may both be symptoms of a common underlying cause, or that increasing depressive symptoms are on the starting end of a dementia continuum in older adults.

Of the 3,000 adults aged 55 and over that were studied, only the group whose symptoms of depression increased over time were found to be at increased risk of dementia - about one in five in this group developed dementia. Those who had symptoms that came and went or stayed the same were not at increased risk.

Signs of depression
The symptoms of depression in older adults can be slightly different, and many of them can be confused with memory loss and illness.

• feelings of helplessness, hopelessness, or worthlessness
• lack of energy and fatigue
• irritability
• pessimism
• loss of interest in activities
• difficulty concentrating or remembering
• confusion
• problems sleeping
• appetite loss or overeating
• aches and pains that don't go away

Your doctor may want to evaluate you or loved one for dementia if you are found to be depressed. If an individual appears to have the beginning of dementia and they are depressed, it's important to treat their depression as soon as possible.

Stress and anxiety
It's not just depression that's a risk factor for dementia. Chronic stress and anxiety has also been found to increase your risk of developing the disease.

A recent review of research found that chronic stress and anxiety can damage areas of the brain involved in emotional responses, thinking and memory, leading to depression and Alzheimer's disease.

Lead author of the review, Dr Linda Mah, said: "Pathological anxiety and chronic stress are associated with structural degeneration and impaired functioning of the hippocampus and the prefrontal cortex, which may account for the increased risk of developing neuropsychiatric disorders, including depression and dementia."

Dr Mah and her team analysed findings from a number of recent studies on fear and stress in animals and evaluated studies which looked at brain scans of anxiety in humans. They concluded that limited episodes of fear and stress pose little cause for concern, but warn that chronic stress and anxiety can "wreak havoc" on immune, metabolic and cardiovascular systems and cause damage to the brain.

While a few days of stress before an exam or job interview is unlikely to cause problems in the future, long-term feelings of stress, fear and anxiety – caused by on-going relationship problems or work stress, for example, could have devastating effects in later life.

If you're concerned about stress, anxiety or depression, it's important to seek help. The good news is that stress-induced damage to the brain is "not completely irreversible" according to Dr Mah. Treatment with antidepressant drugs and exercise have been found to boost regeneration.