Severely depressed patients have elevated hormone levels that could increase their risk of having a Heart attack, but electroconvulsive therapy (ECT) reduces the levels of these hormones to those observed in healthy subjects, a research suggests.

Previous studies have shown that patients who are depressed or who have increased levels of the hormone norepinephrine in the blood have twice the incidence of chronic Heart failure.

To determine if depression is associated with increased norepinephrine levels, researchers studied 10 unmedicated patients with severe melancholic depression and 12 healthy controls. Melancholic depression is a characterized by a daily pattern in mood such that depression is worse in the morning.

Dr. Philip W. Gold, of the National Institute of Mental Health in Bethesda, Maryland, and colleagues measured norepinephrine, epinephrine and cortisol levels in the depressed patients before and after ECT, in which an electrical current is administered to the brain.

Before ECT, the depressed patients displayed significantly higher hormone levels compared with normal individuals. Levels of these hormones rose throughout the night and peaked in the morning - a time of maximal vulnerability to a heart attack.

After ECT, however, depression improved and hormone levels returned to normal.

This study, the researchers say, supports the premise that depression is an illness that affects the whole body and adds to the urgency for diagnosing and treating major depression in patients with heart failure complicated by depression.

SOURCE: Proceedings of the National Academy of Science May 23, 2005.