CHICAGO (CNN) -- Men diagnosed with clinical depression are more than twice as likely to develop coronary artery disease as non-depressed males, according to the results of a long-term study.

"Clinical depression appears to be an independent risk factor for coronary artery disease, even several decades after the first episode [of depression,]" said Dr. Daniel Ford of Johns Hopkins University, lead author of the study reported in the latest issue of Archives of Internal Medicine, a journal published by the American Medical Association.

Johns Hopkins researchers analyzed data from nearly 1,200 male medical students that was obtained between 1948 and 1964. About 12 percent of the students reported one or more episodes of clinical depression. Members of that group were 2.12 times as likely to develop coronary artery disease or suffer a heart attack than men in the other group.

Researchers also said depression was linked to a greater overall risk of death, although it was not found to be associated with a higher risk of stroke.

On average, symptoms of coronary artery disease surfaced in the students about 15 years after their initial bout of depression, researchers found.

While the men suffering depression drank more coffee than those free of the illness, the two groups did not differ significantly in respective levels of blood pressure, cholesterol, cigarette smoking, physical activity, obesity or family history of coronary artery disease.

The latest research added to several previous studies that have shown an association between depression and heart disease, according to Ford, who said a way to further explore the link will be to examine how the dramatic increase in the use of anti-depressants affects coronary artery disease rates.

Symptoms of depression include irritability, marked loss of interest in daily activities, changes in appetite, trouble sleeping at night, daily fatigue or energy loss and recurrent thoughts of death or suicide.

Reuters contributed to this report.