A Common Origin?

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Genetics may be a link between extreme obesity and mental health.
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Genes that have been identified to be associated with mental health may predispose individuals to obesity.

Obesity is often an inherited condition. Many of those who are living with obesity also experience mental health concerns or illnesses. Researchers around the world are trying to understand the underlying factors for why these conditions often go hand-in-hand.

Dr. Satya Dash, Scientist at Toronto General Hospital Research Institute (TGHRI), is using genetic analysis to explore the association between obesity and a variety of mental illnesses.

To do this, Dr. Dash and his team conducted genetic analyses in 149 individuals that were referred to weight loss surgery at the University Health Network. Around 80% of these individuals had experienced mental health concerns. The team found that some rare genetic changes, which were previously associated with conditions such as bipolar disease, schizophrenia and autism, were more common in these individuals.

To confirm that the identified genetic changes were associated with both obesity and mental illnesses, Dr. Dash, in collaboration with Drs. Rachel Batterham and Ingrid Dahlman, compared his results with those from genetic studies of obese patients in the United Kingdom and Sweden.

“We compared our data with these studies because they excluded those with either any mental illness or those with severe mental illness. We did this so that we could see whether exclusion of individuals with mental illness affected the occurrence of genetic changes that we identified,” says Dr. Dash.

As expected, the study that excluded severe mental illness had less of the identified genetic changes, and the study that excluded all mental illness did not have any of the genetic changes. These results support the idea that rare genetic changes identified by Dr. Dash’s team may contribute to both conditions.

Dr. Dash comments, “I hope that these findings help remove some of the stigma associated with living with obesity and mental health concerns, which have a strong genetic basis. The next step will be to translate these findings into effective treatments for patients affected by extreme obesity and mental illness.”

This work was supported by Diabetes Canada, the Banting & Best Diabetes Centre, the Toronto General Hospital Research Institute, the National Institute for Health Research (UK) and the Rosetrees Trust. A Bassett holds a Tier I Canada Research Chair in Schizophrenia Genetics and Genomic Disorders.

Stahel P, Nahmias A, Sud SK, Lee SJ, Pucci A, Yousseif A, Yosseff A, Jackson T, Urbach DR, Okrainec A, Allard JP, Sockalingam S, Yao J, Barua M, Jiao H, Magi R, Bassett AS, Paterson AD, Dahlman I, Batterham RL, Dash S. Evaluation of the Genetic Association Between Adult Obesity and Neuropsychiatric Disease. Diabetes. 2019 Sep 10. doi: 10.2337/db18-1254.

Dr. Satya Dash is a Scientist at Toronto General Hospital Research Institute, University Health Network.