White matter in the brain contains fiber tracts that allow brain cells to communicate with one another by electrical signals. That function makes it a key component of the brain’s wiring. Disruption to white matter has been linked to problems with processing emotion and with thinking skills. Now a new study of more than 3,000 people conducted by scientists at the University of Edinburgh reveals that white matter integrity is reduced in people with symptoms of depression, while those changes were not observed in people with no depression symptoms. The scientists used diffusion tensor imaging to map the white matter’s stucture. Due to the large size of the sample studied, the results are considered to be highly robust. Depression is the world’s leading cause of disability and affects close to a fifth of UK adults over a lifetime. Symptoms include low mood, exhaustion, and feelings of emptiness. The research is an important step toward developing new and more effective methods of treatment.