Most people have days when they feel sad or down. These feelings are natural. However, when these feelings are particularly severe for a significant period of time, and they interfere with a person's ability to conduct their affairs and handle daily life, they may be diagnosed as clinical depression. According to the American Psychiatry Association, major depression disorders are present in about five percent of American men and up to 10 percent of American women. This does not include lesser forms of depression, including minor depression and dysthymic disorder

This number is somewhat higher among heart patients, particularly after open-heart surgery or a heart attack. The National Mental Health Association (NMHA) estimates that depression occurs between 40 and 65 percent of patients who have had a heart attack. Similarly, up to 20 percent of heart disease patients with no history of heart attack are diagnosed with clinical depression. The depression may be a psychological reaction to the prognosis, pain, and/or incapacity caused by the disease or the treatment.

Depression among heart patients is important because it is closely associated with worse outcomes. For example, heart attack patients who suffer from clinical depression are three to four times more likely to die within six months of their heart attack than non-depressed patients. Patients who are diagnosed with clinical depression after coronary artery surgery are more likely to suffer from a cardiac-related problem in the next five years. And atherosclerosis, or “hardening of the arteries,” has been shown to progress more rapidly among depressed patients.

The problem is compounded because heart disease and clinical depression appear to cause and reinforce each other. Depressed patients are more likely to suffer heart disease, and heart patients are more likely to be depressed, thus increasing their chances of worse heart disease.

For these reasons, it is important that heart patients and their families are aware of the symptoms of depression. According to the Diagnostic and Statistical Manual of Mental Disorders IV, which is published by the American Psychiatric Association, a major depressive episode can be diagnosed if five or more of the following symptoms are present in the previous two weeks, and if at least one of the symptoms is depressed mood or loss of interest or pleasure. The nine symptoms are:

1. Depressed mood most of the day, nearly every day
2. Diminished interest or pleasure in activities
3. Significant weight loss or gain
4. Sleep disturbances
5. Agitation or restlessness
6. Fatigue or loss of energy
7. Feelings of worthlessness or guilt
8. Loss of concentration
9. Recurrent thoughts of death or suicide, or suicide ideation

For a major depressive disorder to be diagnosed, the person would have to experience one or more major depressive episodes that are not part of a larger psychiatric pattern of illness, such as manic or schizophrenic episodes. Manic episodes are characterized by elevation of mood, decreased need for sleep, inflated self-esteem, distractability and other symptoms. If a person experiences both depressive episodes and manic episodes, they may be diagnosed with a bipolar disorder. This was formally known as manic-depression.

It is important to note that postpartum depression, which occurs in about five percent of women after pregnancy, is not considered a separate diagnosis by the American Psychiatric Association. It is, however, included on the spectrum of depressive disorders.

A third form of depression is known as dysthymic disorder. A person with dysthymic disorder may be withdrawn and experience little or no joy in life. To be diagnosed with dysthymic order, the following criteria must be met:

• The person is depressed most of the time, almost every day, for at least two years. In children, the time frame is one year.
  
  
• At least two of the following symptoms are present while depressed:
  
• Overeating or lack of appetite
• Sleeping problems
• Fatigue or lack of energy
• Poor self-esteem
• Concentration problems
• Hopelessness
  
  
• There have been no major depressive episodes over the two-year time frame
  
  
• There have been no manic or mixed episodes of depression and mania
  
  
• The symptoms cannot be explained by another chronic disorder
  
  
• The symptoms cannot be explained by the use of substances, either legal or illegal
  
  
• The symptoms significantly interfere with daily function or cause great distress

The symptoms of depression may be slightly different in children and adolescents, in whom depression may be expressed as anger, irritability or temper tantrums rather than sadness. Young people may also show less interest in their friends or classmates, spending long periods of time alone in their room.

According to the National Institute of Mental Health, adolescent depression in girls is more prevalent than in boys. Parents are encouraged to consult regularly with their children’s teachers, who can be invaluable in monitoring behavioral problems and declines in academic performance. This is particularly important, as depression can give rise to self-destructive and even violent consequences. Government research has estimated that as many as half of school shooters suffer from depression. 

The diagnosis of depression, depressive episodes or manic behavior are made only by trained professionals, including psychologists, psychiatrists, social workers or physicians. Part of making a diagnosis includes ruling out physical conditions that may be causing the symptoms, such as hypothyroidism, menopause, and the side effects of prescription medications or drug abuse.

Treatment is available for depression. Strategies often include a combination of antidepressant medications and counseling or therapy to treat clinical depression. It is particularly important for heart patients to seek treatment for their depression because of the negative effects of depression on the body. By treating depression, both emotional and physical health can improve.