When two disorders or illnesses occur in the same person, simultaneously or sequentially, they are described as either comorbid or co-occurring. People with co-occurring physical and mental conditions represent a significant portion of the population. Comorbidity is associated with elevated symptom burden, functional impairment, decreased length and quality of life, and increased costs. Collaborative, integrated care models that use a multidisciplinary team have been shown to provide effective treatment for co-occurring mental and physical health conditions.

Why Depression and Medical Illnesses Often Occur Together

1. Medical disorders may contribute biologically to depression.
2. Medically ill people may become clinically depressed as a psychological reaction to the prognosis, the pain, and/or incapacity caused by the illness or its treatment.
3. Though occurring together, depression and a general medical disorder may be unrelated.

Heart Disease and Depression

• Depression occurs in 40 to 65 percent of patients who have experienced a heart attack.
• After a heart attack, patients with clinical depression have a three to four times greater chance of death within the next six months.

Stroke and Depression

• Depression occurs in 10 to 27 percent of stroke survivors
• An additional 15-40 percent of stroke survivors experience some symptoms of depression within two months after the stroke

Cancer and Depression

• One in four people with cancer also suffers from clinical depression.
• Depression is sometimes mistaken as a side effect of corticosteroids or chemotherapy, both treatments for cancer.

Diabetes and Depression

• People with adult-onset diabetes have a 25 percent chance of having depression.
• Depression also affects as many as 70 percent of patients with diabetic complications.

Common Symptoms of Depression and Other Medical Disorders

• Weight loss, sleep disturbances, and low energy may occur in people with diabetes, thyroid disorders, some neurological disorders, heart disease, cancer, and stroke –and also are common symptoms of depression.
• Apathy, poor concentration, and memory loss can occur in individuals with Parkinson’s disease and Alzheimer’s disease – and also are common symptoms of depression.
• Medications for high blood pressure, Parkinson’s disease, and other medical problems can produce side effects similar to the symptoms of depression.

Importance of Treatment

• People who get treatment for co-occurring depression often experience an improvement in their overall medical condition, better compliance with general medical care, and a better quality of life.
• More than 80 percent of people with depression can be treated successfully with medication, psychotherapy, or a combination of both.
• Early diagnosis and treatment can reduce patient discomfort and morbidity, and can also reduce the costs associated with misdiagnosis, and the risks and costs associated with suicide.