10 Health Conditions That Are Linked to Depression
Depression and co-occurring disorders
Depression has a complicated relationship with other medical conditions, especially chronic ones. In some cases, depression can be a risk factor or an early symptom of another medical condition; in other cases, medical conditions are risk factors or symptoms of depression.
If you think you have depression, it’s important to get screened so that you can find the right kind of help. Left untreated, depression can get worse–and it can make other health concerns worse too.
Here are some co-occurring disorders you should know about.
“People with gastrointestinal cancers, typically stomach or pancreatic, have an increased likelihood of developing depression, and often it can precede the diagnosis,” says Paul B. Hicks, MD, PhD, associate dean at Texas A&M University College of Medicine in Bryan.
Experts aren't sure exactly why this is, but different theories point to immune-system changes and genetics.
Some cancer treatments cause sleep problems, nausea, and loss of appetite, which can in turn contribute to depression. And people who have depression are more likely to smoke, drink alcohol, and to be obese, all of which raise the risk for cancer.
As many as half of people with chronic pain–be it from arthritis, migraine, back pain, or another condition–also have depression. Like with cancer, the link can go both ways: Pain can lead to the release of inflammatory markers that may be connected with mood changes, and ongoing pain may lead to depression.
Depression can also precede the pain. For instance, people with fibromyalgia are three times as likely to have had depression than the average person, says Miggie Greenberg, MD, associate professor of psychiatry at Saint Louis University School of Medicine.
Pain, regardless of the cause, can also be a symptom of depression. “Many people don’t have a lot of vocabulary for psychological feelings and so express emotional distress with physical symptoms,” says Dr. Greenberg. “It’s not that you’re ‘faking’ it. It’s really true.”
In addition to medication to relieve both depression and pain, many people get relief from cognitive behavioral therapy, yoga, acupuncture, and massage.
Your thyroid gland is responsible for regulating your body’s metabolism. Both hyperthyroidism (an overactive thyroid) and hypothyroidism (an underactive thyroid) can lead to depression, although it’s more common with low thyroid levels, says Dr. Hicks.
A diagnosis of depression can also come before any known thyroid problems.
Fortunately, treating thyroid conditions, even thyroid cancer, is fairly straightforward. Thyroid medications are usually very effective for correcting your mood.
Other symptoms of a thyroid disorder include hair loss, gaining or losing weight, fatigue, and feeling cold. If you have any of these symptoms–with or without depressed mood–consider having your thyroid checked out.
Mood disorders are more common in people with heart disease than in those with healthier tickers: Up to 33% of people who’ve had a heart attack end up with depression, according to the American Heart Association. The risk of heart disease is also higher among people who have depression. And having depression can interfere with your recovery from heart disease, already the number-one killer of American men and women.
“[Depression] is one of the warning signs that you’re going to have a bad prognosis” after a heart attack, Dr. Greenberg says. That’s at least partly due to the fact that depression can make it harder to eat right, exercise, take medications, and do the other things necessary to get healthy again after heart problems.
There’s also evidence that people with depression may have extra-sticky platelets, which can lead to atherosclerosis, a major risk factor for heart attacks.
Lupus may cause your immune system to attack brain and nerve cells, which can contribute to depression. The stress of dealing with lupus and its symptoms–like unexplained fever, fatigue, joint pain, or rash–on an everyday basis may also lead to depression, as can some lupus medications.
Depression and diabetes–both type 1 and type 2–may be intertwined in several different ways. Taking care of diabetes is a stressful, full-time job, which can spark mood changes. And having depression makes it that much harder to take your meds, eat right, and exercise–and skipping those healthy habits can make the depression–and the diabetes–worse.
Researchers also think diabetes and depression may share several common pathways, including genetic, hormonal, and immunological causes. Diabetes may also cause tiny lesions in the brain that could be involved in depression.
Having HIV or AIDS is no longer the death sentence it once was, but it can still come with depression and, again, the relationship is a complex one.
The HIV virus itself can directly damage the brain, leading to depression or HIV dementia (which may be mistaken for depression), according to the American Psychiatric Association. Some HIV medications–like Sustiva (efavirenz) and Retrovir (zidovudine)–can make depression worse.
Make sure you get depression screening if you have HIV or AIDS. Feeling low can make it difficult to take the steps necessary to keep your viral load under control.
RELATED: 16 Signs You May Have HIV
HIV is not the only infection linked to depression. There are many others, including influenza, herpes, and hepatitis C–as well as the virus that causes chickenpox and shingles.
Experts don’t know the nature of the relationship–if infection causes mood disorders, if depression is a risk factor for infection, or if the two share triggers. One hypothesis is that inflammatory changes may be the common link.
Another infection–tuberculosis–is actually responsible for the development of some antidepressants. In the first half of the last century, doctors noticed that some of the early drugs used to treat TB lifted patients’ mood, Dr. Hicks says. This led to the class of antidepressants known as monoamine oxidase inhibitors (MAOIs).
RELATED: 10 Surprising Antidepressant Facts
Depression is one of the most common symptoms of multiple sclerosis and may appear even before the MS does.
“It can be a warning sign that’s something is amiss and seems to be an indication that MS will be developing,” says Dr. Greenberg. “When you look back and see who gets MS, many of them have had depression, though obviously not for 100% of people.”
MS can damage parts of the brain involved in regulating mood. Depression can also be a result of hormonal changes and changes in the immune system that are common with MS. Corticosteroids, a common treatment for MS, can also lead to depression.
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Vitamin B12 deficiency
Vitamin B12 has a wide range of responsibilities in the body including producing chemicals that affect mood. If you’re low on B12, you can end up not only with depression but also confusion and dementia.
B12 is absorbed through the small intestine; anything that interferes with that ability can cause a deficiency. This includes celiac disease, Crohn’s disease, and weight loss surgery, as well as taking a proton pump inhibitor for heartburn.
Vegetarians are also prone to B12 deficiencies, as the vitamin is only found naturally in animal products like fish, lean meat, eggs, and milk. Many breads, breakfast cereals, and other grains are also fortified with B12.
Other symptoms of a B12 deficiency include numbness or tingling in your hands, legs, or feet; anemia; hallucinations; and fatigue. Talk to your doctor if you think you could have a vitamin B12 deficiency so you can figure out why and correct it.