It’s a vicious cycle: depression increases the risk for chronic illness, and chronic illnesses may bring on episodes of depression.

According to WebMD, up to one third of people with chronic illnesses also suffer from depression. Cardiovascular disease, stroke, cancer, diabetes, and other chronic conditions are strongly associated with depression.

Depression Can Worsen Chronic Diseases

According to a paper by Gregory Simon of the Center for Health Studies published in the Western Journal of Medicine, depression greatly increases the degree of illness in patients with chronic conditions. Patients with depression had almost twice as many days of restricted activity or missed work as who were not depressed. Depression is linked to a 50 percent to 100 percent increase in health services use and costs.

Some behaviors linked to depression may make chronic illnesses worse, including:

• Not following treatment, including not taking prescribed medications
• Being more likely to smoke and drink
• Lack of exercise
• Poor eating habits

Depression can cause physical fatigue, insomnia, anxiety and anorexia or binge eating. As your body is robbed of quality sleep, good nutrition, and restful periods of “me time,” it begins a downward spiral that puts you at higher risk for disease.

According to a review of 31 studies in Dialogues in Clinical Neuroscience, patients with depression and chronic illnesses experienced a much higher number of medical symptoms, particularly pain and fatigue.

Dr. Nelson Rodriguez, a staff psychiatrist at Cincinnati’s Lindner Center of HOPE, often sees comorbidity in his patients. “I’ve tried to understand the correlation between physical illnesses and mental illnesses,” says Dr. Rodriguez. “One of our roles as psychiatrists is to help educate our patients about the interactions between illnesses.

“I see a number of first-time patients who are overweight, may complain of being tired during the day, or have trouble sleeping,” he explains  “If they have trouble sleeping, I may refer them to a specialist for a sleep study to find out if they have sleep apnea. Once that is treated, they may experience relief from their symptoms of depression.”

How Chronic Illness Impacts Depression

The National Alliance on Mental Illness (NAMI) writes that dealing with a chronic illness can lead to “uncertainty, grief, sadness, anger or fear.” But if these feelings continue beyond a few days and affect normal daily functions, it may be a sign of depression.

A NAMI fact sheet suggests that diet, exercise and good habits – along with medication and/or talk therapy – can help ease symptoms of depression and chronic illness. NAMI advises patients to try to remain involved in activities or learn new skills, maintain a daily routine, keep an active support network and practice proper self-care.

The Cleveland Clinic advises patients to seek treatment for depression, stating, “Those with chronic medical conditions who get treatment for co-existing depression often experience an improvement in their overall medical condition, achieve a better quality of life, and find it easier to follow through with their treatment plan.”

Most treatment studies have found that talk therapy and antidepressant medications are effective in treating depression in patients with depression and comorbid illnesses.

Even if depression and chronic illness go hand in hand, it’s not an unbreakable bond. Speaking up, asking for help, and working with a health care team to establish the proper treatment can increase patients’ motivation for self-care and reduce symptoms.