Let’s be real: We can’t always see the glass as half full. Sometimes we feel a little down, and that’s perfectly normal. But intense depression is another story. It’s longer lasting and interferes with work, relationships and other everyday activities. In extreme cases, it can lead to feelings of utter hopelessness and suicidal thoughts or acts. This form of severe sadness is called clinical depression, and it’s more common in people with multiple sclerosis than in the general population.

It’s understandable because MS is a challenging autoimmune disease that damages the myelin sheath covering neurons in the brain and spinal cord and can cause a wide range of serious symptoms, including severe depression. In fact, several studies report that the incidence of clinical depression at some point in an MS patient’s life may be 50 percent or higher.

[See: 10 Lessons From Empowered Patients.]

A 2015 Canadian study published in the journal Neurology showed that women with MS are more likely than men to develop depression, but men with the disease develop depression at a much higher rate compared to men without MS.

There’s also evidence, according to a 2015 Italian study in the journal Psychology, Health & Medicine, that during the first year after an MS diagnosis, patients are more likely to suffer with serious depression.

Dr. Leorah Freeman, assistant professor of neurology at McGovern Medical School at UTHealth in Houston, agrees. “There are two critical periods when MS patients are more likely to experience episodes of depression and anxiety,” Freeman says. “The first is right after diagnosis when there’s a period of adjustment and a decreased sense of self worth,” she says. “Another time is when there’s a major change in function, particularly if it affects a patient’s ability to work or care for oneself.”

What are the other causes of such high rates of severe sadness among MS patients? “In general, having to deal with a chronic disease such as MS, with its many difficult symptoms — among them visual problems, extreme fatigue, muscle weakness, cognitive fog and balance issues — can cause depression,” says Dr. Geoffrey Eubank, chief of neurology at OhioHealth in Columbus. “But that’s only one possible trigger.”

Eubank continues: “Secondly, the high incidence of depression in MS patients may also have to do with the particular damage to the myelin sheath around the nerves responsible for helping the brain send signals that modify mood. If those nerves are misfiring, than the mechanism that works to correct mood won’t be functioning correctly.”

[See: Am I Just Sad — or Actually Depressed?]

There’s another contributing factor. “Depression can be a side effect of drugs prescribed for MS symptoms, particularly those in the interferon family, often used to treat acute relapse,” Eubank says. “But it’s not the same for everyone. Patients react to interferon medication differently, so the same drug that contributes to depression in one person with MS may not cause it in someone else. And there seems to be some evidence that certain MS medications are more likely to increase the risk of depression in someone who already has a history of mood disorders.”

If you, or your doctor, think your medication may be to blame for your depression, there are other ways to approach your disease. “Your doctor might change your medication or prescribe an antidepressant, as well as suggest other treatments such as counseling,” Eubank says.

How do you know if you’re suffering with depression? According to the National Multiple Sclerosis Society, symptoms of clinical depression include:

— Sadness and or irritability

— Loss of interest or pleasure in everyday activities

— Loss of appetite — or increase in appetite

— Sleep disturbances — either insomnia or excessive sleeping

— Agitation or slowing down behavior

— Feelings of worthlessness or guilt

— Problems with thinking or concentration

— Persistent thoughts of death or suicide

Suicide appears to be twice as likely among those with MS, according to a study published in the April 2014 issue of the Journal of Psychosomatic Research.

[See: The Many Ways Exercise Fights Depression.]

“It doesn’t matter whether you have MS or not; clinical depression is always to be taken seriously,” Eubank says. “Seeing a mental health professional, getting on a medication designed to treat depression, joining a support group, reducing stresses in your daily life and exercising regularly are some ways to deal with the condition.”

But the most important thing you can do is to let your doctor know how you’re feeling. “Don’t suffer in secrecy,” Freeman advises. “When one of my patients expresses feelings of depression, I remind them that depression is not shameful. It can affect anyone of us; it’s not a sign of poor character.”

Freeman adds: “It’s very important to be able to speak openly with your neurologist, or someone who can coordinate care with a mental health specialist and distinguish between transitory changes in mood from clinical depression. If it’s depression, it’s necessary to take a proactive and prompt approach.”

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What’s the Connection Between MS and Depression? originally appeared on usnews.com