A frankly shocking number of both physical and mental health conditions have been linked to a higher risk of depression — and in some cases, a much higher risk. It is important to recognize depression in this patients in a timely manner, because because the two diagnoses have a nasty tendency to interact to make the overall prognosis worse.
Physical health conditions linked to depression
One meta-analysis (a kind of study that looks at the outcomes of various other studies) estimated that a total of 33 percent of stroke victims become depressed, though the authors acknowledged that it is really hard to get an accurate picture of the true prevalence of depression in this group of patients.
Because research has shown that people who experienced a major stroke are more likely to become depressed than those who had a minor stroke, indicating that more limited physical abilities and a loss of independence is a large contributor. A stroke can also, however, induce physical brain changes that increase the risk of depression.
2. Heart disease
Up to 40 percent of people with heart disease are thought to be depressed, while an additional 20 to 30 percent has low-level depressive symptoms that don't quite meet the diagnostic criteria. But — get this! — being depressed also predicts a higher risk of coronary heart disease in the future. This link goes two ways, then.
The explanation, scientists have found, lies in high triglyceride levels and the presence two inflammatory proteins (IL-6 and CRP) — biomarkers also often found in people suffering from treatment-resistant depression. These two diseases seem to have common risk factors, in other words.
3. Chronic pain
Chronic pain, as a result of any cause, can overshadow a person's whole life and rob them of their ability to participate in the things they want to do. Perhaps it is no surprise that over 60 percent of patients attending a specialized pain treatment center were found to be depressed, with just over a third suffering from severe depression.
Research has discovered that around four in 10 people living with the central sensitivity syndrome fibromyalgia will be depressed at any given point in time. One aspect of this is chronic pain, which we've already established is strongly linked to higher depression rates. Fibromyalgia is also often triggered by stressful events, such as injury, which can also precipitate depression, however.
5. Multiple sclerosis
Just under a third of multiple sclerosis patients are estimated to suffer from major depressive disorder. The high rate of depression in MS sufferers can be explained by a combination of factors — the fact that multiple sclerosis can have a huge negative impact on daily life, of course, but also the fact that MS destroys the protective coating around the nerves (myelin), which can alter the way in which the brain reacts.
Cancer patients, who face a much-feared disease, are estimated to become depressed three times more often than people without cancer. This poses a serious threat, because research also indicates that depressed cancer patients have a 25 percent higher risk of dying, while 70 percent of oncologists believe that mood impacts the progression of cancer itself.
Because depression is one of the very symptoms of hypothyroidism, it is no surprise that 60 percent of people suffering from it reported "some degree" of depression. The link is so strong that anyone with major depressive disorder who isn't responding to antidepressant treatment and/or talk therapy should ideally be tested for hypothyroidism, while endocrinologists treating the condition should also be screened for depression.
Depending on where they live, as many as a third of HIV-positive people are estimated to suffer from depression. This can be explained by a combination of worries about health, discrimination, and a decreased ability to engage in employment in some countries. Antiretroviral drugs, while life-saving, also often induce side effects that are difficult to tolerate, and many HIV+ people suffer from poor sleep quality.
Mental health conditions linked to depression
8. Anxiety disorders
Around 50 percent of depressed people are estimated to also suffer from an anxiety disorder, with possibilities including generalized anxiety disorder, PTSD, agoraphobia, and social anxiety disorder. Though the reason why isn't totally clear, many people will have shared risk factors, like traumatic experiences, and similar brain chemistry imbalances may lead to both depression and anxiety.
Various studies that sought to find out how common it is for adults with ADHD — or attention deficit hyperactivity disorder — to become depressed came up with rates varying from just under 19 percent to over 40 percent. Because ADHD has only been taken seriously as a disorder in adults since recent times, much more information on this topic should emerge in the near future.