Head or Heart

Schizophrenia is mostly associated with psychiatric symptoms, including hallucinations, psychosis, and delusion. But could there be a somatic, less mentally focused component to the disease that we don’t yet fully understand? A recent paper in The American Journal of Psychiatry has established a genetic link between cardiovascular disease (CVD) and schizophrenia (1).

It was previously known that schizophrenia carried an increased risk of CVD in individuals – up to two- to threefold greater in some cases (2) – but the mechanisms behind this link have historically not been well understood. For example, there is a recorded prevalence of lower BMI in those diagnosed with schizophrenia at the moment of diagnosis, yet those with schizophrenia are also more likely to be obese. In a bid to reveal the potential genetic causes for the increased risk, researchers analyzed genome-wide association study (GWAS) results for any genetic architecture shared between schizophrenia and CVD risk factors.

The study found that a significant number of genetic variants that underlie schizophrenia also have an effect on CVD phenotypes.The team stated that they discovered “extensive genetic overlap” between two groups of risk factors. The team also identified certain specific areas in the genetic code that are shared between schizophrenia and CVD related factors, such as BMI, blood pressure, type 2 diabetes, waist-to-hip ratio, heart disease, among others. 

The paper concludes that there is an “inherent propensity” to smoking behaviors in those with schizophrenia. Interestingly, a number of risk loci for schizophrenia are protective against CVD-influencing obesity. More research that leverages even larger GWAS datasets will be needed to explore the genetic reasons behind these comorbidities in greater detail.