Psychological and physical disorders are found to co-occur more often than can be explained by chance. New research by genetic epidemiologists from Vrije Universiteit Amsterdam and Amsterdam UMC shows that depression and cardiovascular disease are connected through a combination of genetic predisposition, environmental factors, and direct effects of the conditions on each other.

The findings by Prof. Dr. Eco de Geus (Biological Psychology, VU Amsterdam), Dr. Jorien Treur (Psychiatry, Amsterdam UMC), and Prof. Dr. Brenda Penninx (Psychiatry, Amsterdam UMC) have been published this week in the scientific journal Nature Cardiovascular Research under the title “Genetic perspectives on the co-morbidity of anxiety and mood disorders with cardiovascular disease.” These insights may contribute to better collaboration between mental health care and cardiology.

Three causes behind this connection

Anxiety and mood disorders, such as depression, are strikingly common among people with cardiovascular disease. To understand why these conditions so often co-occur, researchers analysed a large number of genetic and epidemiological studies. The link between depression and cardiovascular disease is explained by three factors:

• Shared genetic predisposition: certain genetic factors increase the risk of both psychological and physical disorders.
• Shared environmental influences: for example, low socioeconomic status, prolonged stress, and unfavourable living conditions.
• A direct effect of depression on cardiovascular disease: people with depression have an increased risk of developing cardiovascular conditions.

No evidence for the reverse relationship

The researchers based their conclusions partly on twin studies and large-scale genetic studies investigating DNA differences. These so-called genetically informative research designs make it possible to better distinguish causal relationships from coincidental associations.

The results indicate that anxiety and mood disorders can increase the risk of cardiovascular disease. For the reverse relationship—that cardiovascular disease leads to psychological disorders—the researchers found no convincing evidence.

Results from randomised treatment studies also support this conclusion. Treating depression appears to have beneficial effects on heart and vascular health, whereas treatment of cardiovascular disease does not consistently lead to improvement in psychological symptoms.

Significance for Healthcare

According to the researchers, the findings highlight the importance of a joint approach to mental and physical health. In practice, these are often still treated separately, even though many risk factors actually overlap.

An integrated approach to care, in which psychiatrists, psychologists, GPs, and cardiologists work together, may provide better support for patients. In particular, interventions focused on stress reduction, lifestyle improvement, and prevention seem promising for reducing the dual burden of mental and physical health problems.

Societal Impact

The results are relevant for a growing group of patients dealing with multiple conditions at the same time. By recognising and treating psychological symptoms earlier, it may also be possible to reduce the risk of serious cardiovascular disease.

The researchers therefore call for greater attention to the interaction between mental and physical health. Better collaboration between different medical disciplines can not only improve patients’ quality of life, but also help to reduce the societal and economic impact of chronic illness.

source: VU Amsterdam Onderzoek onthult oorzaken samenhang tussen depressie en hart- en vaatziekten – Vrije Universiteit Amsterdam