Susan Williams, widow of comedian Robin Williams, revealed that she and her husband "were living a nightmare" the months before his death.

An emotional Williams told in an interview with ABC's Amy Robach, "My best friend was sinking". The interview was aired Tuesday, Susan's first after Robin Williams commit suicide in August 2014.

Far from what most people think, she said, it wasn't depression, or any longtime struggles with alcohol and drug addiction that caused her husband's death.

According to Susan a "chemical warfare" inside her husband's brain drove him to suicide. A "chemical warfare" that no one knew about.

Doctors conducting an autopsy to Robin Williams discovered that he has Lewy body dementia.
Not nearly as well known "Alzheimer's disease", Lewy body dementia, or LBD, is the second most common type of progressive dementia. About 1.4 million Americans have this type of disease but it's a comparatively "young disorder".

According to Angela Taylor, director of programming of the Lewy Body Dementia Association, the number of people having this kind of disease is likely much higher.

LBD is caused when common proteins in the brain starts to combined, forming clumps called Lewy bodies that, as they multiply, "muck up the ability for the brain to transmit signals," stated by Dr. James Leverenze, a Cleveland Clinic neurologist.

The symptoms of LBD are like Alzheimer's disease that includes cognitive troubles such as confusion, reduced attention span, and memory loss. LBD also affect patient's locomotors skills, their moods, making it a "triple threat," Taylor explained.

"It's not just memory, it's not just movement, and it's not just behavior. It's a combination of all three, which makes it difficult to diagnose and difficult to treat," Leverenz confirmed.

Susan Williams recalls her husband's complaint about different ailment, sleeplessness and constipation.

She said, her husband felt some "sense of relief" after being diagnosed with early onset Parkinson's disease in May 2014. She is also hopeful because she knew Parkinson has a cure unlike with Alzheimer's that has no cure.

Susan Williams breaks down after remembering what she witnessed on July 24, 2014. She was within the shower when she saw her husband lingering by the sink. After opening the door she found him holding a bloodied towel, a severe gash on his head.

Williams said LBD affected his husband's vision and his ability to identify objects, like the door.
"Lewy body dementia killed Robin," she said to Robach.