How is Schizophrenia Genetically Linked to Cardiovascular Risk Factors?

People with schizophrenia have a genetic predisposition to higher cardiovascular (CVD) risk factors, particularly smoking and body mass index (BMI). Schizophrenia patients exhibit higher nicotine addictive behavior and a lower BMI reflecting low obesity risk (1^✔ ✔Trusted Source
Characterizing the Shared Genetic Underpinnings of Schizophrenia and Cardiovascular Disease Risk Factors

Go to source). The study was published in The American Journal of Psychiatry.

Unraveling Schizophrenia’s Genetic Link to Smoking & Obesity

Schizophrenia is associated with an increased risk of CVD and this study was aimed at better understanding the genetic overlap between the two. The research team, led by Linn Rodevand, Ph.D., with the Norwegian Center for Mental Disorders Research at the University of Oslo, analyzed recent genome-wide association study (GWAS) results to estimate the number of shared genetic variants and pinpoint specific shared locations. Extensive genetic overlap was found between schizophrenia and CVD risk factors, particularly smoking initiation and BMI. Several specific shared locations were also found between schizophrenia and waist-to-hip ratio, systolic and diastolic blood pressure, type 2 diabetes, lipids, and coronary artery disease.

The genetic overlap between schizophrenia and smoking behavior means that people with schizophrenia may be more affected by nicotine’s addictive properties, the authors note.

“In particular, patients with schizophrenia experience greater reinforcing effects of nicotine and more severe withdrawal symptoms during abstinence.” In addition, they note that “smoking may represent a form of self-medication . . . tobacco smoking in people with schizophrenia may involve, to some extent, an attempt to compensate for genetically determined dysfunction of nAChRs.”

Schizophrenia’s Genetic Link to Cardiovascular Risk Factors

In line with previous evidence of a higher prevalence of low BMI before the onset of schizophrenia, the study results also indicate that people with schizophrenia are genetically predisposed to lower BMI. However, obesity is also more common in individuals with schizophrenia than those in the general population.

The findings indicate that factors other than common genetic variants play an important role in weight gain in schizophrenia, including adverse effects of antipsychotics and symptoms, depression, and socioeconomic challenges that contribute to unhealthy lifestyles. In addition, genetic factors likely play an important role in antipsychotic-induced weight gain.

The overlapping locations between schizophrenia and lipids, blood pressure, waist-to-hip ratio, type 2 diabetes, and coronary artery disease had mixed effects directions. This means that half of the genetic variants influencing schizophrenia were associated with increased cardiovascular disease risk, while the other half were associated with reduced cardiovascular disease risk.

This may suggest that subgroups of people with schizophrenia vary in their genetic vulnerability to CVD, which can underlie some of the differences in CVD comorbidity, according to the authors.

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Reference:

1. Characterizing the Shared Genetic Underpinnings of Schizophrenia and Cardiovascular Disease Risk Factors - (https://ajp.psychiatryonline.org/doi/10.1176/appi.ajp.20220660)

Source: Eurekalert