Heart attack patients, and most likely those with other forms of heart disease, run an increased risk of developing post-traumatic stress disorder, says a new research review done in Denmark and the Netherlands.

This may lead to a vicious cycle, with the PTSD associated with heart disease harming the patient's future cardiac heath, according to the study in the current issue of Psychosomatic Medicine.

Among heart attack patients, about 15 percent develop the psychiatric disorder, according to review authors Helle Spindler of the University of Aarhus, Denmark, and Susanne S. Pedersen, of Tilburg University, the Netherlands.

"PTSD has been shown to lead to impairments in social functioning, vitality, physical health and health status; increased psychological distress and adverse prognosis," write the researchers. Also, preliminary findings suggest that PTSD may heighten the risk of noncompliance with treatment.

The authors reviewed 25 studies conducted since 1980 that looked at PTSD after one of the following cardiac events: myocardial infarction (heart attack), sudden cardiac arrest, cardiac surgery, heart transplantation or congestive heart failure. The studies reported either an absolute number of PTSD cases among the patients or a prevalence rate -- how often the condition occurred within a larger group -- for PTSD.

Among the 25 studies reviewed, the prevalence of PTSD after heart disease ranged from zero to 38 percent. However, the researchers note that some of the studies are based on very small numbers of patients; populations studied ranged from 23 patients to 2,325 patients. The authors found that PTSD has been most rigorously studied in relation to heart attack and that the best studies showed a 15 percent prevalence rate for PTSD in these patients.

Coronary artery disease remains the leading cause of death in the Western world despite being highly treatable.

The authors identified six groups of risk factors increasing the likelihood of PTSD in CAD patients:

-- Personality traits or types such as neuroticism or distressed personality

-- Aspects of the cardiac event itself, such as the patient's perception and reaction to it

-- Certain specific psychiatric symptoms -- dissociation and acute stress disorder -- at the time of coronary artery disease

-- Lack of social support

-- Demographic factors such as being female or of relatively younger age

-- Prior psychiatric history and prior trauma

Spindler H, Pedersen SS. Posttraumatic stress disorder in the wake of heart disease: prevalence, risk factors, and future research directions. Psychosomatic Medicine 67(5), 2005.