Mood and Cognitive Function
Alireza Atri, MD, PhD: The other thing that can affect cognitive function is mood. Marc, how do you think about the effect of mood on cognitive functioning?
Marc E. Agronin, MD: It’s so important, as has been discussed, to look at some of these risk factors because you might be dealing with reversible changes in cognition. It’s wonderful when you can really have an impact on someone’s life by identifying a factor like that. It’s wonderful when you can address it and they’re better. Sometimes it’s the cause of what’s going on. Sometimes it’s just worsening it. Mood is a good example.
Severe depression can mimic dementia. There’s a condition called pseudodementia, where individuals, particularly older individuals, look like they have an early stage of Alzheimer disease or some form of dementia. They don’t have good motivation, there are personality changes, and they’ve just slowed down in general. But what’s really going on is an underlying depression. When you treat the depression, they get better and the cognitive changes go away. That’s good news on 1 front.
But we also know that probably for up to a third of these individuals, this is actually a prodromal stage of dementia. So we need to follow them very carefully over time, because their risk of developing an actual dementia is quite high. But it really speaks to the impact of mood not only as a risk factor chronically. We know chronic depression, especially later in life, is a risk factor for developing dementia, possibly because of the effect on increased cortisol rates on brain cells. But in addition, someone who’s depressed is not taking as good care of themselves. They might be missing medications that can have an impact on cardiac function, or can increase the risk of cardiac events or stroke. So it might be direct or indirect, but that link is really clear.
I would also add that so many of the individuals I work with who have dementia, when they’re depressed, they do worse. Their function is worse. They’re not socializing as much. They’re clearly suffering more. And so, by treating the depression we really have a great impact on them. We also have a great impact on the caregiver. Caregivers also suffer from higher rates of depression, and so they also need to be factored in to the equation and often need treatment as well.
Alireza Atri, MD, PhD: And I should have actually said depression, but also anxiety, because that’s the other part of the issue. We hear stories from our patients that things that they used to do routinely now cause them anxiety—travel, appointments. At that point, it seems that cognition just bottoms out.
Marc E. Agronin, MD: It’s true. For any of us, if we were beginning to have more difficulty organizing our day, we’re going to be more anxious. That’s a given. But when you think about it, part of addressing anxieties are our internal scripts in which we’re able to put things into perspective. We’re able to organize things and come up with a plan to try to reduce the anxiety. But when those executive functions are waning and a person is less able to do that, the anxiety can peak. It can cause frank panic attacks. And that’s why, sometimes, we see these exaggerated responses to stress from individuals for whom, in the past, we never would have seen that. That’s anxiety. The good news is that we can treat it. We have lots of different ways to address that. But it can be such a form of suffering for someone. And so, it’s so important that we readily jump in and help them with that.
Alireza Atri, MD, PhD: I think a take-home point is that there’s the pseudodementia, and anxiety, and also depression that is treatable in many. There’s also pseudodepression, which is a manifestation of a brain disease, like Alzheimer disease, that can be a prodrome for many years. So either way, if you think about anxiety, depression, mood changes in an older individual, we have to think about doing a cognitive assessment.
Marc E. Agronin, MD: It’s true. And clinicians need to understand the difference between depression and apathy. Apathy is a disorder of motivation. Depression is a disorder of mood. The 2 can look identical, but knowing the difference can make all the difference in terms of clinical approaches to it.
Transcript edited for clarity.
