10 Medical Conditions Linked to Depression

Cancer

Feeling sad, angry, or anxious can be expected when you have cancer. Still, clinical depression is also common among cancer patients, according to the National Cancer Institute, especially with certain types of the disease.

"People with gastrointestinal cancers, typically stomach or pancreatic, have an increased likelihood of developing depression, and often it can precede the diagnosis," said 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.

Per the National Cancer Institute, risk factors such as having cancer pain that is not well controlled, feeling physically weakened, having a poor prognosis, or taking certain medications, may also cause depression.

Chronic Pain

One 2016 study published in the journal Pain found that approximately 60% of patients with chronic pain also presented with depression. Like 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 pain. For instance, people with fibromyalgia are three times as likely to have had depression than the average person, said 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," said 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, according to the U.S. Pain Foundation.

Thyroid Problems

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, said 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.

According to UpToDate, other thyroid disorder symptoms include hair loss, gaining or losing weight, fatigue, and feeling cold. If you have any of these symptoms–with or without a depressed mood–consider having your thyroid checked.

Heart Disease

Mood disorders are more common in people with heart disease than those with healthier tickers: Up to 20% of people who've had a heart attack could develop 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 and other heart conditions, according to a 2014 review in the journal Circulation.

"[Depression] is one of the warning signs that you're going to have a bad prognosis" after a heart attack, Dr. Greenberg said. That's partly because depression can make it harder to eat, exercise, take medications, and do the other things necessary to recover 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, according to Johns Hopkins Medicine.

Lupus

Depression is common with autoimmune diseases, and lupus, a disease that spurs your immune system to attack your organs and tissues, is no exception.

A 2016 study published in the Journal of Immunology Research found that depression was associated with the level of lupus disease activity and its effects on the brain. 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, according to the Lupus Foundation of America.

Diabetes

Depression and diabetes–both type 1 and type 2–may be intertwined in several ways. Managing diabetes can be draining, which can spark mood changes, according to the American Diabetes Association. And depression makes it that much harder to take your meds, eat right, and exercise–and skipping those healthy habits can worsen depression and diabetes.

Researchers also think diabetes and depression may share several common pathways, including genetic, hormonal, and immunological causes, according to a 2014 review in Current Diabetes Reports. Structural changes to certain parts of the brain may also play a role. Per a 2020 study published in Scientific Reports, depression in people with type 2 diabetes may be associated with damage to areas of the brain involved in mood control.

HIV

Living with the human immunodeficiency virus (HIV) or AIDS (acquired immunodeficiency syndrome, which HIV causes) can be stressful. Per the Centers for Disease Control and Prevention, depression is one of the most common mental health conditions persons with HIV face.

HIV 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.

Other Infections

HIV is not the only infection linked to depression. There are many others, including influenza, herpes, hepatitis C, and the virus that causes chickenpox and shingles.

Experts don't know the nature of the relationship–if the 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, according to a 2020 review published in Neuron.

Multiple Sclerosis

Depression is one of the most common symptoms of multiple sclerosis and may appear even before MS does.

"It can be a warning sign that something is amiss and seems to be an indication that MS will be developing," said Dr. Greenberg. "When you look back and see who gets MS, many of them have had depression, though obviously not for 100% of people."

According to a 2014 review published in Nature Reviews Neurology, MS can damage parts of the brain that regulate 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, per MedlinePlus.

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 might experience symptoms of depression, as well as confusion and dementia, according to a 2013 study in the Open Neurology Journal.

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 types of bread, breakfast cereals, and other grains are also fortified with B12.

According to MedlinePlus, other symptoms of a B12 deficiency include numbness or tingling in your hands, legs, or feet, anemia, hallucinations, and fatigue. Talk to your healthcare provider if you think you could have a vitamin B12 deficiency so you can figure out why and correct it.