The World Health Organization, or WHO, reports that depression affected some 121 million people worldwide in 2004, making it the fourth leading contributor to the global burden of disease. By the year 2020, the Centers for Disease Control and Prevention, or CDC, predict that the prevalence of depressive disorders will be second only to heart disease. Depression is categorized by type and level of severity; however, the risk of mortality for depressed individuals exists for not only those diagnosed with major depression, but also those who suffer from subclinical forms of depression, who often don't get diagnosed or treated. When depression is combined with other chronic conditions, a patient's outcome is usually poorer. The National Institutes of Health suggest that in many cases, depressive disorders are life-threatening.
Infant and Child Mortality
The infants and young children of depressed mothers have a higher chance of being exposed to risk factors for child mortality. Depressed mothers are more likely to stop breast-feeding and not follow through with their children's immunizations---the former leading to higher rates of infant mortality. Babies of mothers with depression are five times more likely to show signs of malnutrition and poor growth compared to other infants, reports the CDC. They also experience significantly more episodes of diarrhea, which is a leading cause of infant death in developing countries.
Suicide
Depression in young people increases their chances of engaging in risk-taking behaviors such as drug and alcohol abuse and early sexual experimentation and increases their risk of being diagnosed with conduct disorders and adult depression. Depression in teens is also a risk factor for suicide, which is one of the major causes of adolescent mortality in developed countries. In the United States alone, teen suicide has tripled in the last 40 years, making it the third leading cause of death for 15- to 24-year-olds and accounting for nearly 1 out of every 7 deaths in this age group, reports the WHO.
As people grow older, depression continues to increase the risk of mortality exponentially. The WHO states that depression among the elderly is suspected as the cause of most self-inflected deaths and that the suicide rate is higher in this age group than in any other---at least 15 percent for those with untreated depression---especially in elderly men.
Effects on the Heart
Depression and depressive symptoms increase the risk of developing coronary artery disease 1.6 times compared to the risk in nondepressed individuals. According to the CDC, nearly 1 in 6 persons who have had a heart attack also have major depression, and at least half of them experience significant depressive symptoms. The risk of heart attacks is also significantly higher in people who are depressed, increasing the chances of heart attacks for individuals with high levels of depressive symptoms; for those with a history of major depression, the chance of having a heart attack is four times higher than that of people who have no clinical history. Patients who have experienced a heart attack and are depressed are at even greater risk for mortality.
In patients who have undergone coronary artery bypass surgery, state of mind plays a role in recovery and, thus, affects mortality. Research conducted by the University of Maryland and Columbia University's medical centers posits that depressed patients who have undergone heart bypass surgery are two times more likely to die within 7 years from coronary problems than patients who show no signs of depression after surgery.
Effects on Other Chronic Illnesses
The WHO suggests that depressive disorders are associated with an increased prevalence for chronic diseases. The organization states that the former may serve as a precursor to the latter, and that chronic disease also exacerbates the symptoms of depression.
Being severely depressed leads to a twofold increase in the chance of having a stroke within 10 years. Stroke mortality is also higher among depressed patients. To make matters worse, depression often follows strokes---particularly those affecting the left side of the brain---impairing response to rehabilitation and increasing mortality up to two years after a stroke.
People with diabetes are 1.5 to 2 times more likely to suffer from depression, which increases their chances of being sedentary. In many depressed patients with diabetes, a lack of impulse control often leads to overeating sweets and fatty foods, as well as a lower rate of compliance with a diabetic diet when away from home. Combined with poor metabolic control and decreased quality of life, depression contributes to a higher mortality rate in patients with diabetes.
Being HIV positive and having depression increases the risk of disease progression and mortality.
References
- World Health Organization: Mental Health, Poverty & Development
- Centers for Disease Control and Prevention: The Vital Link Between Chronic Disease and Depressive Disorders
- "Depression in Young People and the Elderly"; Eduardo Sabaté; October 2004
- "Eastern Mediterranean Health Journal"; Behavioural and Clinical Factors Associated with Depression Among Individuals with Diabetes; Z. Yekta, R. Pourali and R. Yavarian; March 2010
- American Psyciatric Association: Age, Gender May Determine Impact of Depression, Mortality Link
