Dementia in your 20s or 30s sounds impossible, almost like a medical myth. Yet for neurologist Nick Fox, it has a face, a history, even a heartbreaking routine. He has treated people barely out of college whose lives were quietly unraveling while everyone around them blamed stress, depression, or relationship problems. The memory lapses weren’t always the first clue. Instead, it was the eerie loss of drive, the strange new obsessions, the sudden coldness where warmth used to live.

Partners watched, confused and ashamed, as their once‑attentive loved one walked past them crying on the kitchen floor, not out of cruelty, but because their brain no longer registered the pain. That is the cruelty of frontotemporal dementia: it rewires who a person seems to be. Fox’s warning is simple and urgent—if someone young changes so deeply that they feel like a stranger, don’t just explain it away. Ask questions. Seek help. And don’t assume youth is a guarantee of a healthy mind.