Mental health and dementia risk

It is an unfortunate truth that many of my patients with dementia also have difficulties with their mental health.

This is understandable and may occur due to the psychological adjustment to having cognitive impairment, along with the diminished ability to effectively navigate day-to-day life. This can invoke a sense of loss, sadness and anxiety.

We also know that the underlying pathology associated with the dementia – such as the brain accumulation of misfolded proteins in Alzheimer’s disease and Lewy body dementia, or the reduction  in cerebral blood flow in vascular  dementia – can predispose the affected person to depression, anxiety or other psychological symptoms.

Complicating matters, the loss of nerve-cell function in dementia means that the medications that are effective for treating these mental health difficulties in younger, cognitively intact people may be less effective the further along the journey a patient is.

What about mental health problems before dementia, though? There is increasing evidence that symptoms such as anxiety, depression and apathy may be harbingers of dementia: the early signs that herald the later cognitive decline. This is important to recognise, not just because the symptoms need treating, but also because, if they do represent the start  of a dementia process, it is best to pick this up early.

The other question I’m often asked is whether mental health difficulties increase the risk of dementia. Though the research is not 100 per cent conclusive on this matter, there does seem to be a signal supporting this. Clinical depression has been associated with a doubling of risk, and PTSD perhaps a little more. Chronic, clinically debilitating anxiety also seems to increase the risk, though not quite so much.

I should point out that I am talking about clinically diagnosable conditions, and not just the largely manageable and time-limited stress that we all experience periodically in life, or transient feelings of sadness or low mood we may feel in response to life difficulties. It is really the more severe and protracted symptoms that we worry about. These mental health problems can cause a state of inflammation in the body and brain. This might be one way they increase the risk of dementia.

They also have been associated with changes in brain structure, such as a shrinking of the hippocampus: a phenomenon also seen early in Alzheimer’s disease. Encouragingly, though, treating these conditions effectively can decrease inflammation and even increase the size of the hippocampus, ameliorating the risk.

Feelings of depression and anxiety can lead to other issues that in themselves heighten dementia risk. These include social withdrawal as the sufferer does not want to be around other people. The subsequent isolation and loneliness can be a real problem for the brain, and with less social contact, there is less cognitive stimulation – again a suboptimal situation for our grey matter.

We live in an area where mental  health difficulties are often very treatable.

Knowing the dementia connection is double the reason to talk to someone if there is a problem.

 Kailas Roberts is a psychogeriatrician and author of Mind Your Brain: The Essential Australian Guide to Dementia, available at bookstores and online. Visit yourbraininmind.com or uqp.com.au