Chronic pain, or depression, has long been associated with both types of pain and causes, with around 40% of adults with chronic pain developing clinical symptoms of depression. Researchers from the UK Biobank cohort conducted neuroimaging brain scans from 14,462 participants from the study. They compared participants who reported chronic pain for at least seven years without depression to those who also developed depressive symptoms. These findings suggest that a treatment such as minocycline could prevent depression in people with persistent pain, particularly if treatment is introduced early. The researchers also found that the hippocampus, a structure that plays important functions in learning and memory, was particularly affected by chronic stress. The findings were not specific to a single type of chronic pain condition and were studied using rodent animal models.