How Mental Illness Leaves Its Mark on the Brain

"Yet these experiences do not float free of the body. They are grounded in the brain itself. With its folds, ridges, and layers, the brain carries both the machinery of thought and the marks of our genetic inheritance. A new study shows just how deeply the two are connected. The very genes that increase vulnerability to psychiatric disorders also help shape the brain's physical architecture."

"The cortex, the wrinkled outer layer of the brain, is where memory, perception, and higher thought processes occur. Scientists measure it in two ways. Surface area measures how widely the folds of the cortex extend. Thickness refers to the depth of the cortical layers. By combining brain scans from people with large-scale genetic data, researchers discovered that the same genetic variants linked to conditions like depression, schizophrenia, and autism also shape both cortical thickness and surface area."

"The overlap between genetics and brain topography is not simple. The study identified 55 genetic regions where psychiatric risk and cortical surface area are linked, and 29 regions where psychiatric risk and cortical thickness are connected. Some variants enlarged or thickened brain regions, while others reduced their size or thickness. These bidirectional effects reveal why earlier studies often missed the connection. If some genes increase brain measures and others decrease them, the average cancels out."

Dozens of genetic sites link psychiatric risk to cortical structure, with 55 regions tied to surface area and 29 tied to thickness. Cortical surface area measures how widely cortical folds extend; thickness measures the depth of cortical layers. The same genetic variants associated with depression, schizophrenia, and autism also influence both cortical thickness and surface area. Some variants enlarge or thicken regions while others reduce size or thickness, producing bidirectional effects that can cancel in averaged analyses. Patterns of effects cluster across the brain, separating higher-order association regions from sensory regions and indicating organized topographic relationships between genetic risk and cortical architecture.

Read at Psychology Today