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• Robin Williams suicide: Hallucinations from Lewy bodies dementia could have been factor
The illness often accompanies Parkinson's disease, the neurological condition that Williams had been suffering from for three years. But people with Lewy bodies can respond extremely badly to Parkinson's medication. Before his death, Williams had been racked by depression, anxiety and paranoia - and complained to wife, Susan Schneider, about the way his medication made him feel.
Peter identifies with these emotions. "I can understand the impact it must have had on him. You think that if someone is intellectually very competent, they can cope, but it's not necessarily true. I can well understand him experiencing depression from Lewy bodies and that driving him to the edge. I have no qualms about admitting it - I've been to the edge. I've tried to commit suicide twice."
He was diagnosed with DLB in July 2000, yet is skilled at hiding the trauma he was been through. Quick to smile, quicker to make a joke at his own expense, he attributes his survival to his upbeat attitude.
"I've got a terminal disease - a death sentence. And the truth is, you don't know at what rate it's going to happen. I'm told that 15 years is quite exceptional. But the reality is, I have checks with my neurologist and psychiatrist every six months, and my brain is still degenerating. The little proteins floating around in my head are increasing in number."
These "little proteins" are Lewy bodies, the deposits that build up inside nerve cells in the brains of sufferers. DLB, named after the doctor who identified it, was discovered only in the Nineties, and researchers don't fully understand why the proteins appear or how they contribute to dementia.
It is thought their presence is linked to low levels of essential brain chemicals (such as dopamine) and to a loss of connections between nerve cells. Over time, these cells and the surrounding brain tissue disintegrate.
Symptoms vary, and overlap with Alzheimer's and Parkinson's. Hallucinations and sleep disorder are more commonly associated with DLB, but sufferers can also experience the loss of motor function that is characteristic of Parkinson's, and the memory loss linked to Alzheimer's.
Like Robin Williams, who had a tremor in his left arm and restricted motion in his hand, it is Peter's movement that is most affected. He has difficulty writing and uses a wheelchair. "It's not because I can't stand up or walk," he says, "but because I have no coordination. My left leg would walk one way and my right the other."
To watch his withered, shaking hands hover over the keys of the piano he used to play with such gusto is heartbreaking. The music, he says, is there in his head, but his fingers simply don't know what to do.
Peter relies on the support of his family - his wife Ann, to whom he has been married for 55 years, daughters Rachael, Elizabeth and Suzanne, and grandchildren Eleanor and Lois - to get him through his darker moments.
"I'm the recipient of the diagnosis but the truth is, it's a diagnosis to us all."
Ann has stood by his side from the moment both of their lives changed for ever. "We drove home from hospital and sat on the patio," he remembers. "It was a beautiful summer's day and the sun was shining, and suddenly we burst into tears. It was a period of mourning. For three months, this mourning continued, just between the two of us. Then we got on with our lives."
Ann is, he says, absolutely essential to his life. "I don't know what I'd do without her. Nor do I know what I'd do without my children. They were very upset initially - they still are - but they know their dad wouldn't be happy if they started to mope about it.
"So they take it on the chin, give me support when I need it, and laugh and joke with me the rest of the time."
Peter has been prescribed three types of drugs designed to improve nerve cell communication: donepezil hydrochloride (Aricept), memantine (Ebixa) and rivastigmine (Exelon), of which he is on the maximum possible dose. He also takes anti-epileptic drugs to control his tremors. Of the suggestion that Williams's suicide may have been linked to his DLB being misdiagnosed, and indeed mistreated, as Parkinson's, he believes there is an element of truth. "Unless you know this condition in detail, you can't understand it."
Experts now believe that DLB and Parkinson's are manifestations of the same underlying problem: the brain's ability to process the protein alpha-synuclein - which explains why they often occur together, and are mistaken for one another.
But medical practice recommends diagnosing them as separate disorders, not least because of the adverse effects of mixing medication. The official DLB website warns that sufferers of the condition may be "extremely sensitive or may react negatively to certain medications used to treat Alzheimer's or Parkinson's."
Peter still suffers from devastating depression, which has worsened with his illness. Like Williams, he has trouble sleeping - and sleeps downstairs, separately from his wife. "I hate those nights when it's dark and I'm alone," he admits. "When I'm in a solitary mood, and I'm not sleeping, I may have a bad patch. There are occasions when I sit on the edge of my bed sobbing my heart out. But I go into that, and then I'll come out of it."
Peter leads a busy life - he is governor of a mental-health trust and speaks extensively about DLB at national and international conferences - but it is hard to think ahead. "I don't let myself plan years in advance, but I do let myself plan 12 months in advance."
He no longer suffers from hallucinations ("touch wood"), but has seen his motor symptoms worsen over time. "It makes you doubt yourself and your ability to carry on a normal life," he explains. "And the one thing you're trying to do is carry on a normal life. Unless you give up - which a lot of people do, unfortunately." A lot of people - including Robin Williams.
"It's terrible - it must have been so traumatic for the man," sighs Peter. "It's not in my nature to give in. But put that into the situation of another person - especially one in public life - and it could well flick them over the edge. That's the disaster of this terrible disease."
Where to get help
• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youth services: (06) 3555 906
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (4pm to 6pm weekdays)
• Whatsup: 0800 942 8787 (noon to midnight)
• Depression helpline: 0800 111 757 (available 24/7)
• Rainbow Youth: (09) 376 4155
• CASPER Suicide Prevention
If it is an emergency and you feel like you or someone else is at risk, call 111.