Robin Williams’ death in 2014 hit the world like a punch to the gut. For decades, he’d been the electric force behind some of the most memorable films ever made — Good Will Hunting, Dead Poets Society, Mrs. Doubtfire, Aladdin, the list goes on.

He had that rare spark, the kind that felt endless and effortless. On screen, he was unstoppable. Off screen, he was warm, deeply thoughtful, and painfully human. So when news broke in August 2014 that he had taken his own life, it felt impossible. How could someone so full of light reach a place that dark?

At first, people speculated — depression, addiction, burnout. The usual explanations tossed around when the public tries to make sense of tragedy. But the truth turned out to be far more complex, and far more devastating. After his autopsy, doctors discovered that he had been battling severe Lewy body dementia — an aggressive, destructive neurological disease that he never knew he had. His wife, Susan Schneider Williams, later shared what the doctors told her: his brain was full of Lewy bodies. Every region was being impacted.

She said she didn’t even know what Lewy bodies were until they explained it, but once she understood, everything clicked. The confusion. The anxiety. The strange cognitive symptoms. The fear he couldn’t articulate. “The fact that something had infiltrated every part of my husband’s brain? That made perfect sense,” she said in an interview years later.

Lewy body dementia is brutal. The National Institute on Aging describes it as a condition that affects thinking, movement, mood, and behavior — and it progresses fast. Dr. Bruce Miller, a leading neurologist at UCSF, said Williams’ case was one of the most aggressive he had ever seen. He even admitted he was amazed that the actor had managed to function at all. The man who had lifted millions with his humor was quietly fighting a war inside his own brain.

In the HBO documentary Come Inside My Mind, there’s a moment that now feels chillingly prophetic. An old interview clip shows Robin being asked about his fears. He answers honestly: “I guess I fear my consciousness becoming, not just dull, but a rock. I couldn’t spark.” That line hits hard now. His internal spark — the quick wit, the mental fireworks — was exactly what the disease was attacking. And he felt it happening.