Text Overview of Video
Professor Nicola Lautenschlager
When we look at common risk factors for cognitive decline and dementia, depression is one of the most prominent ones. One interesting question is, “Why is that the case?” and, “What do we know about this?” One observation is that, especially if people have had several significant episodes of clinical depression throughout their lifetime, that it looks like there is an accumulative risk of depression, in terms of their cognitive health, when they get older. There are some underlying strong hypotheses, which one comes across in the literature, about why increasing numbers of depressive episodes throughout life might increase the risk of dementia later on. One of these hypotheses is that it has to do with the impact of having increased stress hormones in your body, while you go through a depressive episode. For example, one of these stress hormones is cortisol, and we do know that if you have, for a prolonged period, high levels of cortisol in your body, as is the case when you have a depression, it specifically damages the neurons in the hippocampus, which we know we need to lay down new memory, and which is the area which is damaged early in Alzheimer's disease. Therefore, the message for consumers and clinicians is, if depression is present at any time in life, it’s important to diagnose it as early as possible, and to treat it effectively, as early as possible, to reduce the time with having high hormonal stress burden on the brain. It is more the untreated, unrecognised depression which is harmful for future dementia risk, and not so much the well treated depression, if that makes sense.
Another interesting fact is that depression and dementia share many risk factors, and they’re both common. Obviously, an interesting research question is, “How much are they connected, and how much is just the fact that they share common risk factors?” I’ll give you an example. It has been shown that early experience of trauma in childhood, which might be physical, sexual or psychological, is harmful for having a higher risk later on of developing depression. But more recently, it has also been shown that it is a risk factor independently for having a high risk of dementia. That’s just one example. If you look at chronic health conditions, we know that especially cerebrovascular disease or vascular risk factors, like chronic heart disease, chronic hypertension, anything which basically damages the blood vessels and subsequently also the blood vessels in the brain, increases the risk of having depression, but also increases the risk of having cognitive decline. There is actually a specific term for older people, when they experience depression in the presence of many vascular risk factors, which we call “vascular depression.”
When it comes to treatment of depression in older people, the take-home message is, it should be treated as aggressively in older people as it is treated in younger people. There is no room for therapeutic nihilism just because a person is older. The good news is that older people very often respond very well to appropriate treatment which, for most people, would be a combination of social support and psychological support, plus use of anti-depressants, and usually general practice is the area where this treatment takes place. Basically, depression is one of the best treatable mental health conditions we have. There are some differences between young and older people. Because of the presence of chronic health problems, there is a percentage of older people with depression who have a poorer outcome in terms of recovery. Meaning they might have more, what we call, treatment resistant depression, or might not be able to be completely free of symptoms. They also can have a higher risk of relapse. So the recommendation is, if they benefited well from an anti-depressant, they should stay on that medication and not stop again, to avoid the higher relapse risk.
A common myth is that older people are less able to benefit from psychotherapy. This goes all the way back to Sigmund Freud, who stated that himself, that if a person is older than 50 years they are too old and rigid to benefit from psychotherapy. It’s quite amusing because when he got older himself and was in his eighties, he actually reversed this statement and said it’s not true, but by that stage people were not listening to it anymore. So older people should be offered psychotherapy, if appropriate. And it has been shown, in research studies, that people who are psychologically-minded benefit very well from, for example, cognitive behavioural therapy, even if they’re older. What is a challenge in the health system in Australia, is that very often, there is a lack of therapists who are specialising in older people with mental health problems.
One important message is that older people with depression should receive adequate treatment and there are regular mistakes happening in this field. One common mistake is that healthcare providers give a too low dose of an anti-depressant, for example, because they are anxious it could have negative side effects. On one hand, obviously it’s important to be careful and older people often do need lower doses, but we see in clinical practice that very often the dosage is not increased to an adequate level, or not given long enough, and then often it’s wrongly concluded that the medication is not working. It’s really important to treat long enough, with the right medication, at the right dosage. This is also important because the longer the older person lives with clinically relevant depression, the more it increases the risk that their cognition is impacted negatively and it increases their risk of dementia.
Another important aspect is how our society thinks about ageing. An argument you hear quite often, for example, from nursing homes is, “Oh yes, if I lived like this person, I would be depressed as well.” So it’s normal for this person to be depressed, so we don’t need to treat it. As a society we need to work on that we all change these attitudes, and say an older person is as much entitled to the best possible healthcare as a younger person, and that this is really a sign of ageism, if we conclude, as younger people, that it’s not worth the effort, or that it’s normal for an older person to suffer.
Depression as a symptom is one of the most common non-cognitive symptoms of dementia. People who have dementia, for whatever cause or reason, have a much higher risk of experiencing symptoms of depression than an older person who does not have dementia. Screening for, and detecting, depression in patients who experience dementia, is very important as, again, it has very poor outcomes for them, if the depression is not recognised. There are quite interesting studies that report very high numbers of depression in, for example, residential care.
Interestingly, when it comes to treatment of depression in people with dementia, more recent research has shown that, unfortunately, the currently available anti-depressant medication is less effective, for example, in people with Alzheimer's disease and, furthermore, that people with dementia often have a higher risk of experiencing negative side effects of the medication. It is important to take that into account when a treatment plan is put together. However, the current recommendation is still, if a person is significantly depressed with dementia, medical treatment with an anti-depressant should be considered. If the depression is rather of a milder nature, then the recommendation is maybe not to use anti-depressants as a first line treatment, but rather try non-pharmacological approaches. So that could mean increasing pleasant activities, making sure the person’s not isolated, increasing social contact, increasing physical activity, nutrition and diet and all these things, and see if that already makes a good impact.
A rather new, but very important field of research, is investigating what we can do to prevent the onset of depression in the first place. So if we could think of a health care system where we reduce, from the outset, the risk for an older person to experience late-onset depression, that would be perfect. The knowledge in this area is still very limited. Again, there is some interesting research highlighting that prevention of depression might be possible, and factors to think about and look at more closely are the social environment of an older person, trying to avoid that the person is isolated or feels disconnected from their community, feels they’re a burden, or can’t actively contribute any more to society, would be important. But equally, to look at their physical health, to manage optimally chronic disease, as it is a strong risk factor for depression. Other areas are, for example, hearing loss and loss of vision, which both are strong risk factors for depression in older people, to screen for that regularly. So it looks like there are quite a number of things we can do as a society to reduce, in general, the onset of depression, and that subsequently obviously also help to reduce the onset of cognitive impairment and dementia.