Both mental health disorders and chronic diseases are common and disabling. These conditions can affect anyone, regardless of age, culture, race/ethnicity, gender, or income. The cause is not entirely clear, but it is believed to be a combination of changes in the brain and other neurobiochemical reactions, lack of functionality, and medication related side effects. Research suggests that people who have depression and another medical illness tend to have more severe symptoms of both illnesses.
The same factors that increase the risk of depression in otherwise healthy people, also raise the risk in people with other medical illnesses. These risk factors include:
- personal or family history of depression
- loss of family members to suicide
- stressful life conditions
- chronic illness
- traumatic experience
- substance abuse
- childhood abuse or neglect
- lack of social support
In some cases, depression appears to result from specific biologic effects of chronic medical illness. Examples of this relationship include central nervous system disorders—such as Parkinson’s disease, cerebrovascular disease, or multiple sclerosis—as well as endocrine disorders—such as hypothyroidism. In other cases, the association between depression and chronic medical illness appears to be mediated by behavioral mechanisms; the limitations on activity imposed by the illness lead to gradual withdrawal from rewarding activities.3
Ongoing research is also exploring whether physiological changes seen in depression may play a role in increasing the risk of physical illness. In people with depression, scientists have found changes in the way several different systems in the body function, all of which can have an impact on physical health:
- Signs of increased inflammation
- Changes in the control of heart rate and blood circulation
- Abnormalities in stress hormones
- Metabolic changes typical of those seen in people at risk for diabetes
According to the NIHM, over 16 million people had a major depressive episode in 2016. This represents 6.7% of the population.
Depression is the most common mental health issue among people who have chronic illnesses and occurs at a higher rate than in the general population.
- Cancer: Depression during or after treatment ranged between 8% and 24%.
- Coronary heart disease: As many as 65 percent of patients with acute myocardial infarction report experiencing symptoms of depression; major depression is present in 15% to 22% of these patients.
- Diabetes: Depression occurrence is two to three times higher in people with diabetes mellitus, the majority of the cases remaining under-diagnosed.
The prevalence rate of depression in people with type 1 diabetes is 12% and nearly 19.1% with type 2 diabetes.
Anxiety appears in 40% of the patients with type 1 or 2 diabetes. The presence of depression and anxiety in diabetic patients worsens the prognosis of diabetes, increases the non-compliance to the medical treatment, decreases the quality of life and increases mortality.
- Epilepsy: Depression is the most common psychiatric disorder in patients with epilepsy, yet it remains under-recognized and under-treated. Depression occurs in 25% to 55% of patients. The suicide rate of persons with epilepsy is more than five times that of persons without epilepsy.
- Multiple sclerosis: Depression rates are as high as 20% and lifetime prevalence rates of 50% are not uncommon. Depression is equally common in other immune-mediated, neuroinflammatory diseases (such as rheumatoid arthritis and inflammatory bowel disease) suggesting that inflammation is a contributing factor to depression in these conditions.
There is some evidence that MS patients may have an increased risk of suicide and this is probably most true for younger male patients and those patients who are socially isolated, severely depressed and have alcohol problems.
- Stroke: Depression is a common and serious complication after stroke. A stroke changes brain function and is thought to be a factor in post-stroke depression in many patients. Nearly 30% of stroke patients develop depression, either in the early or in the late stages after stroke. It is thought that antidepressant medication and therapy can improve functional outcomes.
- Alzheimer’s disease: Experts estimate that up to 40 percent of people with Alzheimer’s disease suffer from significant depression. Identifying depression in someone with Alzheimer’s can be difficult, since dementia can cause some of the same symptoms. Depression appears to be more prevalent during the early and mid-stages of the disease due to the patient’s awareness of their disease.
- HIV/AIDS: Clinical depression is the most commonly observed mental health disorder among those diagnosed with HIV, affecting 22% of the population.
- Parkinson’s disease: Clinically significant depressive disturbances occur in 40–50 % of patients. This may be due to biochemical changes in the brain.
- Systemic Lupus Erythematosus/Rheumatoid Arthritis: The prevalence of major depression and anxiety 24%, depression 30%, anxiety 40%.
Why should clinicians in primary care be alert to the possibility of depression in their patients with chronic disease? Why do they sometimes miss it? And what can they do to manage this distressing mental health problem?
Depression significantly increases the overall burden of illness in patients with chronic medical conditions. Compared with those without depression, medical outpatients with depressive symptoms or disorders experienced decrements in quality of life and had almost twice as many days of restricted activity or missed work because of illness. Similarly, depression is associated with a 50% to 100% increase in health services use and costs.
Depression has also been linked to increased disease-related morbidity and mortality. Depression is clearly associated with a poorer prognosis and more rapid progression of chronic illnesses.
The presence of a chronic medical illness may reduce the likelihood that depression and anxiety will be recognized and treated. The demands of chronic illness management may crowd concerns of depression out of the visit agenda. Providers may also not look beyond a chronic medical illness to explain nonspecific symptoms, such as fatigue or poor concentration. Even when they recognize symptoms of depression, they may defer treatment, believing that “anyone would be depressed” in such a situation.
Yet, somatic symptoms often reflect a combination of medical and psychological factors, and the presence of a clear medical explanation for these symptoms does not rule out depression as a contributing factor. Patients should receive appropriate treatment regardless of whether there is an obvious medical or psychological precipitant to their depression.
So what is the appropriate next step? First, consider whether a medical problem or medication is causing the depressive symptoms; treating the problem or changing the medication may alleviate the symptoms. Exhaustive efforts to rule out medical disorders can delay needed treatment and reinforce the stigmatization of depression as something less than a “real” illness.
Effective treatment of depression reduces depressive symptoms and improves daily functioning and should include consideration for both psychosocial and pharmacologic interventions. Treating depression has also been shown to have a positive effect on biologic indicators of disease severity or progression, such as the level of blood sugar in diabetes or platelet activation in ischemic heart disease.
It is our hope that this primer helps improve awareness for primary care providers on the increased risk of mental health concerns in adults with chronic medical conditions. Many times, depression treatment can improve the overall medical condition, the quality of life, and compliance with a long-term treatment plan.