Recent research suggests that a range of different mental disorders may be linked to a higher risk of developing coronary heart disease (CHD). CHD involves a plaque buildup in the arteries serving the heart, and kills about 600,000 people each year in the U.S., the leading cause of death for both men and women.

Dr. Catharine Gale of Edinburgh University, U.K., and her team looked at figures on 1,095,338 men born in Sweden between 1950 and 1976. All had psychiatric and medical assessments during tests for military conscription, and were followed up for about 22 years using a national register of hospital admissions and causes of death.

The men diagnosed with mental disorders at around the age of 18, as well as those who were admitted to hospital for psychiatric disorders at a later age, were at a raised risk of developing CHD.

Analysis showed an increased risk of non-fatal or fatal CHD across a range of mental conditions including schizophrenia, bipolar disorder, depression, neurotic disorders, substance use disorders, and personality disorders. For example, the risk was raised by 30 percent with depressive disorders and by 92 percent with alcohol-related disorders (although this may be due to the alcohol consumption itself).

The highest risk was seen in men whose mental condition was severe enough to require admission to the hospital. Raised CHD risk was not significantly linked to smoking, alcohol intake, blood pressure, diabetes, level of obesity, intelligence, or socioeconomic status measured at age 18.

Full details appear in the journal Circulation. The researchers explain that depression, anxiety, and psychotic disorders have previously been linked to an increased risk of CHD, but it was unclear whether this association with heart disease applies to a wider range of mental disorders.

“Our findings suggest that mental disorders pose a huge public health burden in terms of premature illness and death due to CHD,” said Gale. “The physical health care of people with mental disorders needs to be a priority for clinicians if this burden is to be reduced.”

Commenting on the study, Dr. Karina W. Davidson of Columbia University Medical Center, New York, said other studies have not replicated this “somewhat startling finding” that mental disorders and psychiatric symptoms are independent risk factors for CHD.

She writes that the research on this topic “has been characterized by incomplete adjustment for confounders, wide variation in the assessment of mental disorders, and inconsistent inclusion of multiple mental disorders and overlapping symptom clusters.”

The most convincing evidence of a link comes from studies which link a depression diagnosis to later CHD, she explains, but “although there have been glimpses of associations of other types of mental disorders, such as alcohol/substance use disorder, anxiety, and schizophrenia, with incident CHD, there are a paucity of studies examining this risk.”

Davidson’s own search of the literature on mental disorders and CHD found 123 studies on the topic, of which about 60 percent looked only at depression, 10 percent at alcohol/substance use disorder, 11 percent at anxiety or post-traumatic stress disorder, and 14 percent at psychosis or schizophrenia.

“Thus, outstanding questions about the nature and consistency of the association of specific types of mental disorders, other than depression, and incident CHD remain,” she said.

One such study with less than watertight methodology was carried out by Dr, Kate M Scott and her team at the University of Otago, New Zealand. Although they assessed the presence of 16 DSM-IV mental disorders by questionnaire, their measure of heart disease was by self-report.

The team conducted face-to-face household surveys of 52,095 individuals in 19 countries. Results suggested that depression, panic disorder, phobia, post-traumatic stress disorder, and alcohol use disorders were linked with a 30 percent to 60 percent raised rate of CHD. Those with more mental disorders had an increasingly high risk. Earlier onset CHD was linked most strongly to mood disorders and alcohol abuse. All links were present for both genders.

The team explains in the International Journal of Cardiology that previous studies have tended not to use diagnostic measures of depression, or take other mental disorders into account. If these results are confirmed in future prospective studies, the team writes that, “the breadth of psychopathology’s links with heart disease onset has substantial clinical and public health implications.”

In the February 2006 issue of the Harvard Mental Health Letter experts outline a possible cause of the link.

“Mind and mood can affect the cardiovascular system directly by creating a state of emergency readiness, in which stress hormone levels rise, blood vessels constrict, and heartbeat speeds up,” the newsletter states.

“If a person is seriously depressed or anxious, the emergency response becomes constant, damaging the blood vessels and making the heart less sensitive to signals telling it to slow down or speed up as the body’s demands change.”

But it adds that selective serotonin reuptake inhibitor antidepressants (SSRIs) “may benefit depressed heart patients and possibly reduce their risk for future heart problems.” In addition, cardiac rehabilitation can “sustain patients’ morale and urge them to take better care of themselves.”

This article first appeared on Psych Central on 4 May, 2014.