Depression is common in multiple sclerosis (MS) — significantly more common, in fact, than in the general population or in people with other chronic diseases. More than 50 percent of people with MS will experience a major depressive episode at some point during the illness.

Depression is generally unrelated to the time since diagnosis or to the level of disability. In other words, it can occur early in the disease in people with little or no disability. So it isn’t just a reaction to the challenges of living with a chronic, unpredictable disease; it’s also a symptom of the disease itself.

What do we mean by depression? Many people use the term so often and so casually in everyday conversation — “I’m so depressed,” “This job is really depressing me,” or “This book is so depressing” — that they tend to lose sight of what depression really is.

We’re not talking about having a down day or feeling discouraged or blue about a lousy date, a disappointment at work, putting on a couple of pounds, or even a chronic disease. What we’re talking about is a serious medical condition, referred to as clinical depression or major depression, which can have significant consequences for your health and well-being.

People who are depressed carry an additional, unnecessary emotional burden. They can’t enjoy life, engage with others, or participate actively in their own care. And, they’re difficult to live with. As if that weren’t enough, we know that depression can make other symptoms feel worse — in fact, depression can make just about everything feel worse.

Depression can also affect cognition, making it even harder for people with cognitive issues to do important stuff like think clearly, remember things, and focus their attention without getting distracted. So getting help for depression is an important part of taking charge of your life and your MS.

Severe, untreated depression can lead to death. Studies indicate that the rate of suicide in MS is significantly higher than in the general population. In fact, it’s a leading cause of death in MS after cancer, heart disease, and stroke.

Even though it seems clear that depression is as much a symptom of MS as a reaction to it, the exact cause for the depression isn’t known. Researchers have found changes in the brain and in the immune system of people with MS who are depressed that don’t appear in people with MS who aren’t depressed.

We also want to mention here that some of the medications currently used to treat MS may increase the risk of depression, or worsen existing depression, in some people. For example, the following medications have the potential to affect mood:

  • Corticosteroids: When taking high doses of these medications to treat an MS relapse, some people feel energized — almost giddy — but then find themselves going into a real funk as they come off of them. If you have a history of depression, make sure that your physician is aware of this when corticosteroids are prescribed.

  • Interferon medications: These medications (Avonex, Betaseron, Extavia, and Rebif), which are approved to treat relapsing forms of MS, each carry a warning about depression. But because depression is so common in MS, teasing out the relationship between these medications and mood changes can be very difficult — kind of a cart-and-horse issue. And it appears that most people — but not all — who experience depressive episodes while on these medications have a history of depression.

The bottom line is that the labeling of each of these medications contains a warning about depression, causing some patients and doctors to be reluctant to use them.

The consensus among MS experts is that these medications are very safe. However, if you have a history of depression, you and your doctor may want to consider one of the other approved disease-modifying therapies. And if you’re taking an interferon medication and experience a significant change in your mood — with or without a history of depression — talk about it with your doctor.

Depression is a treatable condition, but there are challenges. The biggest challenges to treatment are the reluctance of people to seek help for it and the failure of clinicians to diagnose it accurately and manage it aggressively.

People don’t like the idea that MS can wreak havoc on their emotions as well as their bodies, and they’re often embarrassed to discuss it. These feelings are certainly understandable, but they aren’t a good enough reason to deprive yourself of the means to feel better and get on with your life.