Is There a Correlation Between Depression and Later Development of Dementia?

Check out this answer from Consensus:

There is a significant correlation between depression and the later development of dementia. Early-life depression appears to be a risk factor for dementia, while late-life depression is often a prodrome of the condition. Shared neurobiological mechanisms and the potential impact of depression treatment on dementia risk highlight the complexity of this relationship. Further research is needed to clarify these associations and develop targeted interventions.

The relationship between depression and the later development of dementia has been a subject of extensive research. Understanding whether depression acts as a risk factor, a prodrome, or a consequence of dementia is crucial for developing effective preventive and therapeutic strategies.

Key Insights

• Depression as a Risk Factor for Dementia:
  • Early-life depression is consistently associated with an increased risk of developing dementia later in life1 3 4 6 7 8.
  • Depression, particularly when it occurs before the age of 60, increases the odds of developing dementia1 9.
• Depression as a Prodrome of Dementia:
  • Late-life depression is often seen as a prodrome, indicating the early stages of dementia1 3 4 6 9.
  • Depressive symptoms in the years immediately preceding a dementia diagnosis may reflect the early neurodegenerative processes of dementia1 3 4.
• Shared Pathophysiological Mechanisms:
  • Both depression and dementia share common neurobiological changes, such as hippocampal atrophy, vascular disease, and neuroinflammatory processes2 3 4 6 7.
  • Elevated cortisol levels, amyloid-beta accumulation, and deficits in nerve growth factors are implicated in both conditions2 4 6.
• Impact of Depression Treatment:
  • Effective treatment of depression may potentially reduce the risk of developing dementia, although more research is needed to confirm this3 4 9.
  • Long-term antidepressant treatment might decrease the risk of certain types of dementia, depending on the type of depressive disorder9.
• Confounding Variables and Heterogeneity:
  • The association between depression and dementia is influenced by various confounding factors, and there is substantial heterogeneity across studies1 5 6.
  • The type of depression and the criteria used to diagnose it can moderate the relationship between depression and dementia risk5 9.

 

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Is there a correlation between depression and later development of dementia?

Enrico Mossello has answered Near Certain

An expert from University of Florence in Geriatrics

Late-life depression is a well-known antecedent of dementia. Evidence is mixed regarding the association between ealy onset depression and late-life dementia. While the pathophysiological association is discussed, the role of depression as prodromal symptom of dementia is well established

 

Is there a correlation between depression and later development of dementia?

Jennifer A Yates has answered Near Certain

An expert from The University of Nottingham in Psychology, Epidemiology

Data from longitudinal studies suggest that depression at the first point of measurement is associated with the development of dementia or a progression of cognitive impairment that can indicate a higher risk for dementia at the second time point (see YATES, J. A., CLARE, L. and WOODS, B., 2015. Subjective memory complaints, mood and MCI: A follow-up study Aging & Mental Health). Meta-analyses – pooled results of previous research – suggest that depression may be a risk factor for cognitive decline (see YATES, J. A., CLARE, L. and WOODS, B., 2013. Mild cognitive impairment and mood: A systematic review Reviews in Clinical Gerontology. 23(4),).

It might be that depression and dementia share common pathways within the brain, or alternatively it could be the acknowledgement that cognitive function is not at the same level that leads to feelings of sadness. Changes within the brain associated with dementia begin up to 15 years prior to symptoms being detected on neuropsychological tests, but people themselves may feel an awareness of such changes. Research has shown that people who do not acknowledge a memory impairment tend not have mood problems such as depression YATES, J. A., CLARE, L., WOODS, B. and MATTHEWS, F. E., 2015. Subjective Memory Complaints are Involved in the Relationship between Mood and Mild Cognitive Impairment Journal of Alzheimer’s disease. 48(1),).

Without further longitudinal data it is difficult to determine the direction of the relationship.

 

Is there a correlation between depression and later development of dementia?

Donald R Royall has answered Near Certain

An expert from University of Texas Health Science Center at San Antonio in Psychiatry, Internal Medicine

In my opinion this is almost certain. Still, there is a lot of room to quibble. First, dementia is not just cognitive impairment, it is disability due to cognitive impairment. Depression is clearly a disabling condition. It is also likely to have cognitive effects. Are the cognitive impairments of depression disabling?

That is not an easy question to answer. Not all cognitive impairments contribute to disability. My recent work identifies general intelligence (g) as the main cognitive correlate of functional status. Depressive symptoms adversely affect g. So, I buy that depression is a potentially dementing illness (not a “psuedodementia“).

Depression increases the risk of dementia conversion, and depressive symptoms are common in recently diagnosed “AD” cases. Anti-depressant use may protect against dementia conversion. So, is there a “dementia of Alzheimer’s Disease (AD)”? Is the association between depression and AD explained by plaques and tangles? My analyses suggest not.

Instead, I think a current depressive episode pushes g closer to its threshold for conversion to clinical dementia. Depression should then increase the risk of any dementia’s diagnosis, not just AD’s.

However, what if the patient is not currently depressed but has a history of that condition? Young onset recurrent depression is associated with brain atrophy. That might also be associated with cognitive changes, independently of any current depressive illness. If depression-related atrophy is associated with g, it could then increase dementia risk, up to many years later, and the risk of any dementia’s diagnosis, not just AD’s.

Can antidepressants reverse this risk? Maybe. Some probably improve cognition. Others may adversely affect it. However, to prevent or delay dementia’s onset, they will have to improve g. I don’t think the current generation of antidepressants are “smart drugs”. One sign of this is that the time course to functional recovery after “successful” antidepressant treatment is similar to that of untreated major depression. Antidepressants are validated for their effect on mood, not cognitive impairment, and certainly not g.

 

Is there a correlation between depression and later development of dementia?

Robert Barber has answered Near Certain

An expert from University of North Texas Health Science Center in Genetics

Numerous studies have confirmed that the heritability of Alzheimer’s (the degree to which disease risk is influenced by genetics) is quite high – in the range of 80%. However, we have identified genes that account for only about half of this genetic risk, including the gene that imparts the greatest amount of genetic risk; the epsilon 4 allele of the apolipoprotein E gene (APOE4). APOE encodes a protein that is involved in lipid transport, but how it increases Alzheimer’s risk is not fully understood. The source of the missing half of the genetic risk is a mystery currently. It is possible that some of this hidden genetic risk is contained in genes that contribute to risk for diseases that are associated with Alzheimer’s and other forms of dementia, including diabetes, hypertension and heart disease, as well as depression and obesity. It is also possible that modifications to DNA, rather than changes to the actual DNA sequence are responsible. These so-called ‘epigenetic’ factors include addition of methyl groups to the DNA strand which influence whether, and to what degree, a gene is used or remains silent. Epigenetics can be thought of as a way for cells to to turn on or off specific regions of DNA.

 

Is there a correlation between depression and later development of dementia?

Joe Herbert has answered Likely

An expert from University of Cambridge in Neuroscience

I agree with Robert Barber. I’d add two further points:

1. The distinction between genes (‘nature’) and environment (‘nurture’) is now known not to be what is usually assumed: that they are separate influences. We now know that there are genetic variations that, for example, incline people to take risks: this will affect their experiences. Conversely, there are experiences (eg maternal deprivation) that alter the expression (activity) of certain genes for long periods, maybe a lifetime. So each can alter the other, and what we are really considering is a mixture of influences. All this applies to disorders such as Alzheimer’s. The old distinction (nature vs nurture) no longer applies.
2. Alhzeimer’s (AD) is not a single disorder, so the factors that encourage or reduce its incidence will vary accordingly. In some cases, for example, very early onset AD, there may be rare genetic variants that play a huge part in the risk. But most cases are ‘sporadic’, and this applies to what Dr Barber says.

 

Is there a correlation between depression and later development of dementia?

H Gutzmann has answered Near Certain

An expert from German Association of Geriatric Psychiatry and Psychotherapy in Psychiatry

Depression is an accepted risk factor for dementia. The presence of depressive symptoms (particularly in patients with amyloid-positive MCI) is associated with higher progression to dementia and longitudinal cortical atrophy. But it is unclear if this relationship is causal.

 

Is there a correlation between depression and later development of dementia?

Brian Draper has answered Near Certain

An expert from UNSW Sydney in Mental Health, Neurodegenerative Disease

There is no doubt that there is a relationship between depression and the later development of dementia but there is much uncertainty about the nature of the relationship and whether the relationship might indicate causality and the potential to intervene and prevent dementia.

The age of onset of depression is one key factor. Studies of depression with onset in early to mid-life have mixed findings about a relationship with dementia. On balance, most probably show a weak relationship though it tends to be more with vascular dementia and here confounding lifestyle factors such as smoking, lack of exercise, vascular risks, obesity etc account for much of the relationship & probably addressing those factors might improve mood and reduce the risk of the later development of dementia.

Late life depression has a much stronger relationship with the subsequent development of dementia and that is likely due to the mood disorder being precipitated, at least in part, by evolving neurodegenerative (such as Alzheimer’s disease, Parkinson’s disease) and cerebrovascular disease that is part of the lengthy cascade into dementia. So here, the depression is not causal of dementia, but a manifestation of the same underlying neuropathology occurring at an earlier time point.

There is no evidence that treatment of the depression alters these associations in either direction. Some have suggested that ECT might increase the risk of dementia but good studies have debunked that. One approach being looked at is whether cognitive behaviour therapy can help anxious & depressed people make sustained lifestyle changes that may be more important in reducing or delaying the risk of dementia. That is an unanswered question.

 

Is there a correlation between depression and later development of dementia?

Sebastian Köhler has answered Near Certain

An expert from Maastricht University in Epidemiology, Neuropsychology

Many studies, including those that look for consistent correlations across many studies (so-called meta-analyses) found evidence for a correlation. However, whether this correlation does not per se mean that the relation is causal. It might be, but in fact we do not know. Some plausible biological pathways have been put forward. For instance, people with depression show higher levels of stress hormones that can lead to inflammation and death of brain cells. However, it has also been suggested that vascular damage to brain structures controlling emotions might lead to depression on the one hand and cognitive impairment on the other. In that sense, depression is not causally leading to dementia, but both are related to some third factor ‘vascular damage’. If depression evolves for the first time on late life, it might also be a prodromal symptom of impeding dementia, as people might notice that ‘things are not quite as they used to be.’

 

Is there a correlation between depression and later development of dementia?

Paul Naarding has answered Likely

An expert from GGNet Mental Health in Neuropsychology, Gerontology, Psychiatry

this question should be refined to be answered straight away; depression comes in a wide variety of sorts. For people with a (hereditary) form of depression with onset in early life, the relationship is complex. There is some evidence that this form is linked to more cardiovascular disease and thus could lead (via the vascular pathway) to some kind of dementia, especially of the vascular type. It could be that chronic stress, often accompanied by inflammation, is a common pathway, inducing both depression and cardiovascular disease. But this is still somewhat speculative.

On the other hand, some people suffer from depression in later life for the first time and in these cases depression frequently goes together with physical and cognitive frailty of all kinds. Then, as Robert points out, depression could be seen as a prodromal stage or early sign of dementia.

But it has to be stressed that this does not mean that everybody with depression will eventually develop dementia.

 

Is there a correlation between depression and later development of dementia?

Carol Dillon has answered Near Certain

An expert from Consejo Nacional de Investigaciones Científicas y Tecnicas in Neurodegenerative Disease

Depression could be the intial symptom of the development of degenerative diseases such as Azlheimer´s dementia.

 

Is there a correlation between depression and later development of dementia?

Joseph E Gaugler has answered Likely

An expert from University of Minnesota in Gerontology

See Livingston, G., Sommerlad, A., Orgeta, V., Costafreda, S. G., Huntley, J., Ames, D., … & Cooper, C. (2017). Dementia prevention, intervention, and care. The Lancet, 390(10113), 2673-2734, p. 2681 and elsewhere, although it is important to note the pathway from antecedent depression to dementia onset and/or progression is likely complex.

 

Is there a correlation between depression and later development of dementia?

Yuedi Shen has answered Near Certain

An expert from Hangzhou Normal University in Psychiatry

The depression is one of risk factor for later development of dementia,on the other hand, some early stage dementtia patient have depressive symptom.for these patient,they usualy be diagnosed with depression.

 

Is there a correlation between depression and later development of dementia?

M Sami Walid has answered Likely

An expert from Agnesian Healthcare in Internal Medicine

I think the association between long-term depression and the development of dementia is strongly likely due to the presumed sustained laziness of brain activity in cases of depression which exerts a degrading effect on brain physiology and consequently a morbid effect on brain parenchyma, ultimately generating brain pathology. An recent study hinting to the positive correlation between these two entities in patients with Parkinson disease came to the conclusion that “PD patients with post-diagnostic depression had higher incidence of dementia,” as per study by Wu et al:

Wu YH, Chen YH, Chang MH,, Lin CH. Depression in Parkinson’s disease: A case-control study. PLoS One. 2018 Feb 1;13(2):e0192050. doi: 10.1371/journal.pone.0192050. eCollection 2018.