Susan Schneider Williams watched her husband suffer with undiagnosed Lewy body dementia before he killed himself in 2014. Her new film tries to educate others about the condition – and put to rest assumptions about his death

After Robin Williams died in August 2014, aged 63, a lot of people had a lot of things to say about him. There was the predictable speculation about why a hugely beloved and seemingly healthy Hollywood star would end his own life, with some confidently stating that he was depressed or had succumbed to old addictions.

Others talked, with more evidence, about Williams as a comic genius (Mork & Mindy, Mrs Doubtfire, The Birdcage, Aladdin); a brilliant dramatic actor (Dead Poets Society, Awakenings, Good Will Hunting, One Hour Photo); and both (Good Morning, Vietnam; The Fisher King). One thing everyone agreed on was that he had an extraordinary mind. Comedians spoke about how no one thought faster on stage than Williams; those who made movies with him said he never did the same take twice, always ad-libbing and getting funnier each time.