Robin Williams' widow Susan Schneider Williams has written a detailed, painful, but also very beautiful account of the actor's psychological journey, in the year leading up to his death in August 2014.
The actor, famous for some brilliant films including Mrs Doubtfire, Good Will Hunting and Jumanji, suffered from Lewy Body Disease, a term used to encapsulate both Parkinson's and dementia.
His wife Susan wrote a long, open-letter to the Journal of the American Academy of Neurology, so that they might understand the very real emotional turmoil of both the patients they treat directly and the spouses and close family experiencing the disease too.
Speaking of the bond that she shared with her husband, Susan explains:
'We would discuss our joys and triumphs, our fears and insecurities, and our concerns. Any obstacles life threw at us individually or as a couple were somehow surmountable because we had each other.'
She goes on to plumb the depths of her loss:
'I lost my best friend. Robin and I had in each other a safe harbor of unconditional love that we had both always longed for.'
Cataloguing the extent of Robin's illness, she says it was as if Robin had a 'terrorist' living inside his mind.
The actor, whose famous on-screen lines included 'You're only given a little spark of madness. You mustn't lose it', was said to have told her 'I just want to reboot my brain.'
My husband was trapped in the twisted architecture of his neurons and no matter what I did I could not pull him out.
'Robin was losing his mind and he was aware of it. Can you imagine the pain he felt as he experienced himself disintegrating?' she goes on.
You can read the full letter here.