The changes were subtle at first. She uncharacteristically missed some deadlines, then became fixated that there were bedbugs in her apartment. Within days, Cahalan was drowning in an ocean of paranoid delusions and hallucinations. Her boyfriend was cheating on her (he wasn’t). Her father was trying to kill her stepmother (he wasn’t). Then she had a seizure. And another. Soon she lay in a New York intensive care unit, drooling, grunting, lashing out and grimacing. Her blood pressure soared and plummeted. Her memory ebbed away. “Her brain is on fire,” her family was told by a neurologist. “Her brain is under attack by her own body.” Her body was churning out rogue antibodies that spiralled towards the brain. Hers was the 217th reported case worldwide of a type of brain inflammation called anti-NMDA receptor encephalitis. Cahalan was given the right treatment to reset her immune system and made a long journey to full recovery.

She tells me that much of the memory vault from that time is close to empty. “I will never get it back. It’s just a darkness, a place of despair.” But her most striking memories are of her hallucinations and delusions. A floating eyeball. A Buddha statue that smiled at her and stalled her attempt to jump out a window. In one instance, as she was being interviewed by a psychiatric nurse, Cahalan realised that she had the power to age others. The nurse’s face became wrinkled, catapulted into senescence by Calahan’s superpowers. She then “aged” her boyfriend, Stephen, watching his hair turn grey, his face transform into his father’s.

The recollection of these hallucinations remain stronger than anything else, leading her to ask: “Why are these the things I remember whereas reality was gone?” She has found solace in the words of a psychiatrist, who said her selective remembering made sense. “He said I remembered hallucinations because they are high on emotional content, imprinted in the brain, and they’re made from the self.”

A man does not consist of memory alone. He has feeling, will, sensibility, moral being … It is here … you may touch him, and see a profound change.