Robin Williams' widow has told how her husband suffered with symptoms of a little-known disease, before committing suicide without knowing what it was.
In an essay published in the Neurology journal, she wrote how her husband's last words to her - "Goodnight, my love" - "still echo through my heart".
She described how his "larger than life spirit" was crushed by fear and anxiety, a continuous tremor in his left hand, a "shuffling gait", terrible insomnia and "loss of basic reasoning" and memory.
While filming Night At The Museum 3, "Robin was having trouble remembering even one line for his scenes, while just three years prior he had played in a full five-month season of the Broadway production Bengal Tiger At The Baghdad Zoo, often doing two shows a day with hundreds of lines - and not one mistake," she wrote.
"This loss of memory and inability to control his anxiety was devastating to him."
In the essay, entitled The Terrorist Inside My Husband's Brain, Schneider, who is campaigning to raise awareness of the disease, wrote that her husband suffered with Lewy body disease thinking it was Parkinson's.
"How I wish he could have known why he was struggling, that it was not a weakness in his heart, spirit, or character," she said.
She added: "It is my belief that when healing comes out of Robin's experience, he will not have battled and died in vain."