Researchers put 48 people in an MRI scanner and found that heavy smartphone users had less gray matter in the same brain regions that shrink in drug addiction. The study behind this tweet came out of Heidelberg in 2020. They compared 22 people who scored high on smartphone addiction against 26 controls, and the differences clustered in the anterior insula, which processes craving, and the anterior cingulate cortex, which handles impulse control. The ACC also showed less resting activity. And…