Relationship Between Depression and Other Health Conditions

Andrew J. Cutler, MD:Sagar, could we talk a little bit about the interplay between depression and other health conditions, medical and otherwise?

Sagar V. Parikh, MD, FRCPC: Well, we know that depression itself is a heterogeneous illness. There isn’t a single etiology. In part, there may be a subset of people, maybe a very large subset of people that have inflammation at their core. If we just look at it from an epidemiologic perspective, of course, depression and heart disease, depression and diabetes, depression and many other chronic illnesses have much higher rates of comorbidity than you would expect. Is this just a functional consequence of altered depression behaviors? If you’re depressed, you become a couch potato, and then your cardiovascular fitness erodes. Well, yes, sure. That’s part of it but maybe it’s that they share some elements of a common etiology, perhaps a neuroinflammatory one, perhaps something else that is driving both higher rates of depression and higher rates of other diseases. We know that insulin, excretion and resistance, are factors not only common to diabetes, but also it’s actually very common in mood disorders. There’s likely a shared mechanism that is driving the interplay between depression and other medical disorders.

Andrew J. Cutler, MD: It really is fascinating, this bidirectional relationship, isn’t it? There’s more depression if you have diabetes, there’s more diabetes if you have depression, and so on. Greg, let’s talk also about the economic impact of MDD. Give us some sense of what is the larger economic impact of MDD and, especially, untreated or inadequately treated MDD.

Gregory Mattingly, MD: Certainly. It’s the good news and bad news of this illness. The bad news is depression is one of the leading causes of disability now, around the world. Here in the United States, it’s one of the top causes of disability for adults. We see that rates of disability with depression have gone up over the past decade, so while we’ve been winning the battle with a lot of our illnesses such as cardiovascular disease and different types of cancer, disability rates with depression have been getting worse over the last decade. The good news is there are countries around the world, including our own country, the United States in general, that are focusing more and more on mental health. They know that mental health is a primary driver of wellness within our society with a more holistic treatment of depression, looking at that mind-body connection. Why does depression crosstalk with things like diabetes, chronic pain, insomnia, and with inflammation? Then how do we help to move the needle holistically for our patients? It is getting more and more research and more and more emphasis. Employers are starting to look at it. They’re saying, listen, if this is one of the major causes of disability among my workforce and not just disability, but when they show up to work, they don’t get as much accomplished if they’re depressed. This term we’ve talked about, Andy, is called presenteeism. I show up to work, but I’m only getting 70% as much as I would if I was healthy and doing well. That’s getting more and more focus from employers, our federal government, and various research organizations.

Andrew J Cutler, MD: Greg, I think you put your finger on something very important and that is that while we focus on the symptoms of depression, and they’re very important, we also have to look at a bigger picture. We’ve got to look at wellness, quality of life, function, and if the person is feeling like themselves. This of course involves productivity, and this drives the economic impact. Sagar, there are some really big costs associated with depression, both direct and indirect. Can you tell us a little bit about that?

Sagar V Parikh, MD, FRCPC: I think Greg alluded to it. We can think about the total costs as really, a function of 2 things. There are direct treatment costs and then there are all the costs associated with premature mortality, and of course, time off work. Rather surprisingly, the direct costs of depression treatment are only a small fraction between 10% and 20% of the total costs associated with depression. The economic literature looking at this also confirms that this is a pretty universal phenomenon across countries. It’s not just segmented to a few countries. It’s also true even in the developing world where the economic losses due to presenteeism or simply work absence, far outweigh the direct treatment costs. They’re massive. I think one of the reassuring things is that the models we have to deliver treatment right now, is, “Oh, you’re sick. Come to my office and I’ll treat you.” That’s not really that scalable. I’m really excited to see a variety of other treatment models that say, well, we need to have a public health approach to treating depression. Can we use digital tools? Can we use websites to provide some elements of care? Can we do things in our schools? Employers are actually offering much better employee assistance programs than they used to a decade ago. Some of them are preventative like wellness as you were referring to, Andrew, but also some are actually resources whether they’re digital tools or more focused kinds of treatments for workers. Sometimes the workers get the treatment in their workplace. Again, that’s much more scalable meeting the problem where it’s at and much more appropriate given the huge cost of these disorders.

Andrew J. Cutler, MD: We’re not just talking about innovative new medications but really treatment models, treatment systems of care. I guess one thing COVID-19 taught us is how to use telemedicine, which also can maybe broaden our access. Greg, who is doing the bulk of the screening and diagnosing of MDD out there?

Gregory Mattingly, MD: It’s not psychiatrists. There are not enough of us, first of all, but we now know that this is a community condition. Depression doesn’t discriminate. It lives among us. Each of us has probably had a friend, a family member, or a loved one who’s been touched by depression. We now see that the bulk of screening, the bulk of depression prevention, and earlier dimension is being done in the primary care arena. That can be your family practitioner, can be an internist, or can be a nurse practitioner that works in one of your community clinics. Many of our new screening systems, as Sagar was saying, incorporate right into your electronic medical record. Screening each patient with a PHQ-2 [patient health questionnaire-2]. Have you had problems with depression? Have you had problems with anhedonia? Have you had problems where your mood isn’t the way it should be? That’s a screening tool that’s built right into it and it’s considered a quality measure for most of our primary care physicians.

Transcript edited for clarity