It was this – insomnia itself can be a risk factor for depression – that sparked the curiosity of geneticist Mariana Moises Oliveira and her colleagues at the Association for Research Incentive Fund (AFIP) Sleep Institute to look at the genes of a group of 1,042 residents of this city. São Paulo, representative of the population of the largest city in Latin America. After all, our DNA can store good explanations about how one problem relates to another.

The results of this unprecedented scientific project were presented yesterday (the fourth) in Houston, United States, during the conference Sleep 2024The Great American Conference on Sleep. “What our research shows is that depression and insomnia are irreversibly linked by their genetic origin,” says the scientist. “One is not a consequence of the other. They are two diseases that go hand in hand, two sides of the same condition.”

When looking at specific gene variants that increase a predisposition to insomnia and then at genetic variants that increase the risk of depression, what Mariana noticed was a significant overlap. “They have many genetic factors in common,” explains the geneticist, who returned to Brazil two years ago to be a researcher at AFIP, after doing part of her doctorate at the University of Lausanne in Switzerland, and a post-doc at Harvard University.

Mariana has always investigated how small differences in our genes can increase our tendency to develop common diseases. But upon her return to the country, she began applying her knowledge of human genetics to sleep studies, and she states her conviction: “Those who have a high genetic risk for depression also have a high genetic risk for insomnia.” “Which suggests that by taking care of one of these problems, you can likely prevent the other,” he adds.