[A version of this item appears in: Dementia: the Latest Evidence Newsletter (RWHT), Volume 2 Issue 4, November 2011].
This review article examines recent systematic reviews, meta-analyses, and randomised control trials (RCTs) to arrive at an overview of current approaches to the diagnosis and management of patients who develop late life depression. The review is structured under headings which answer the questions:
- What is late life depression and who gets it? The “risk factors” for depression in elderly people are summarised.
- How is depression diagnosed in older patients? This section covers DSM-IV criteria for a major depressive episode.
- Is depression more difficult to diagnose in older adults? Useful scales for depression are summarised, including the Cornell scale for depression in dementia.
- Does depression increase the risk of dementia? Depression is more prevalent in individuals with brain disorders including dementia, Parkinson’s disease, and stroke.
- How is late life depression managed?
- When should I refer and what are the risk factors for suicide in older people?
- Which medication should be prescribed?
- What if first line drug treatment doesn’t work?
- Can older adults benefit from psychological therapy? What is the outlook for older adults with depression?
The Dementia Connection?
Depression is associated with cognitive impairment and increased risk of dementia. The Cornell scale for depression in dementia (CSDD) is suitable for patients with cognitive deficit. While this test is not perfect for diagnosing depression, higher scores indicate the need for further evaluation. The article suggests further investigations to consider when depression is suspected.
One issue for future research involves how to better identify and manage depression in dementia.
Many studies have shown that depression in late life is accompanied by cognitive impairment, memory deficits, diminished executive function, and slower information processing abilities. The term “depressive pseudodementia” has been used previously to cover reversible dementia in depression, but the current authors say this over-simplifies the issue. Two systematic meta-analyses found that late onset depression (over the age of 65) is associated with a twofold risk of dementia, but causal relationships are not explained yet.
Various mechanisms have been suggested to explain the relationship between depression and dementia; including hypercortisolaemia, loss of hippocampal volume, neuro-inflammatory processes, Alzheimer-type pathology, reduced cognitive reserve, and vascular disease. Whatever the exact causal links, these are probably multi-factorial. Vascular changes in the brain have been given the highest attention in the literature so far. Disruption to prefrontal-striatal circuitry by cerebrovascular pathology may possibly result in mood disorders and executive dysfunction. This controversial concept does not appear to be confirmed by postmortem studies however.
There is no evidence yet to support the idea that treating depression in earlier or late life might reduce the incidence of dementia.
This article finishes with a summary of additional educational resources and a list of questions for future research.
Full Text Link (Athens password required).
Rodda, J. [and] Walker, Z. (2011). Depression in older adults. BMJ (Clinical research ed.), September 28th 2011, Vol.343(d5219).