Exploring links between mental disorders and cardiovascular disease
The life expectancy of patients with severe mental disorders such as schizophrenia, bipolar disorder and major depressive disorder is, on average, 15-20 years shorter. In fact, patients have a two to threefold increased risk of dying from cardiovascular disease (CVD) compared to the general population. These numbers have not decreased in recent decades confirming that most patients with mental disorders and comorbid CVD have not benefited from the latest improvements in prevention, detection and treatment of CVD. This is where the EU-supported CoMorMent(opens in new window) project stepped in. “We wanted to investigate the mechanism behind this connection including a potential shared genetic basis between mental disorders and cardiovascular disease. We have now confirmed that there is a considerable genetic overlap between mental disorders and risk factors for CVD,” explains project coordinator Ole A. Andreassen(opens in new window), professor from the Centre for Precision Psychiatry(opens in new window) at the University of Oslo.
Detection of shared genomic associations
In a recent study(opens in new window), CoMorMent studied the genetic overlap between major depression disorder (MDD), CVD and lifestyle and behavioural factors, including individual factors such as educational attainment, smoking status, physical activity, exercise, sleep patterns and loneliness. “We found that cardiovascular diseases share most of their genetic risk factors with MDD. Part of the genetic overlap was explained by shared inflammatory, metabolic and psychosocial or lifestyle risk factors,” notes Andreassen. The method used for these analyses, called the ‘conditional false discovery rate’ approach, was developed in Andreassen’s lab. It allows for the detection of shared genomic associations irrespective of the genetic correlation between the phenotypes. “By using this approach, we have also identified the overlap between risk factors for schizophrenia and, for example, smoking,” says Andreassen. This is set out in a recently published paper(opens in new window). Using recent post-mortem brain single-cell RNA sequencing data generated for the Human Cell Atlas(opens in new window), the project showed that several of these genetic risk variants are active in regulating gene expression in cells of the brain and immune system. Further, one of the project partners, the Karolinska Institute(opens in new window), calculated the relative risk of having a CVD after a diagnosis of mental disorder based on data from the Swedish registries(opens in new window). They found that patients diagnosed with psychiatric disorders are at an elevated risk of subsequent CVD, independent of shared familial factors and comorbid conditions. These results have been replicated in data from the Danish registers and the Estonian biobank.
New insights for healthcare treatment
When it comes to treatment paths, Andreassen believes that the project’s findings have a clear implication for healthcare professionals. “Psychiatric disorders are associated with higher risk of cardiovascular mortality. This suggests that surveillance and treatment of CVD comorbidities should be considered as an integral part of clinical management of people with severe mental disorders.”
