My mother who is 86 has had no short term memory for nine years. She’s been in a nursing home for three years. My grandmother was also demented and died in a nursing home. My mother was 22 when I was born, so perhaps my dementia is close. I need to prepare myself.

My mother and I had a letter published in The BMJ in 2005, supporting the case for assisted suicide in relation to dementia.

We wrote:

EDITOR—You can’t aspire to be patient centred and simultaneously reject assisted suicide. That’s the discomfort that afflicts the Royal College of General Practitioners and other doctors who reject assisted suicide. They cling to a world where “doctor knows best,” a world that is as dead as “politicians know best and so be respectful and follow what we do.”

Of course, assisted suicide is anathema to many. But to an equal number—and probably more—it has the potential to allow a graceful and dignified exit from life.

I (HS) am 75, fit, and enjoying life, although I lost my husband of more than 50 years last year. I’m not lonely, and being on my own allows me to do things that weren’t possible when my husband was alive—like listening to Beethoven string quartets, which he found tuneless and mournful. But my life is diminished, and the work of my life is done. I have no fear of death, but I dislike intensely the idea of being demented and institutionalised. I’m moderately confident that doctors will be able to handle the pain that may come towards the end of life (although I’ve encountered many examples where they failed), but they cannot counter the loss of dignity, personhood, and control that comes with dementia.

If I feel dementia approaching, I could of course kill myself. There’s nothing illegal about that, but I would be reluctant to involve my family and friends—for fear that they might be implicated in doing something illegal. Yet I don’t like the idea of sneaking off and doing it alone, not least because I might mess it up and end up in exactly the state I’d like to avoid. I’d much rather that my doctor help me—isn’t that what doctors are for? Preparing to be demented.

My mother as she was would surely find intolerable the way she lives now. She’d rather be dead.

But my mother is not as she was: she’s as she is, and I’m not sure about how she feels about life. I ask her if she’s happy, and she answers yes. But is she?

I have no doubt that when I’m with her she’s happy. We do the same thing each week. We walk through the green grounds of Springfield University Hospital, what was the Surrey Lunatic Asylum. We talk all the time. My mother uses complex language and has a strong sense of humour. There is much laughter. I never ask her what she had for breakfast. I ask her about the past, yesterday about Dame Dorothy Brock, the headmistress of the school she attended during the war and supposedly the lover of Rupert Brooke. We talk in abstractions, and if there’s a pause she tells me how green and wonderful the trees are. She loves trees. If we meet anybody she congratulates them on how they look. After our walk we go the golf club cafe and drink coffee while I read to her–first my father’s magnificent memoirs and now my brother’s equally magnificent autobiography. We laugh at both of them. We walk back to the home where I seat her next to Joy and tell her I’m just going for a pee. Then I leave. She gets upset if I tell her I’m leaving, but moments after I’ve left she’s forgotten I’ve been there. As I cycle down the hill from the home I’m full of relief that I’m not in the home–but I wonder how long it will be before I am.

But how is my mother when I, my brothers, and our partners are not there? I find it hard to know. The nurses tell us she eats, sleeps, joins in all the activities, but is distressed at times. Sometimes when I arrive she bursts into tears at seeing me and says things like “I’m so glad you’re here. I’ve been feeling awful.” Moments later she’s fine. She’s disinhibited, and I know she’s emotionally labile, although she rarely displays it when we’re together.

Is this an acceptable life? She’s so physically fit it could go on for another 10 years, maybe longer. Only she can answer, and she can’t.

We’ve grown used to how she is. It was once distressing. Now it’s not. I’ve even begun to think it’s maybe not so bad. My brother tells the story of my mother watching the news and saying “What a terrible world. Thank goodness I’m not in it.” And she isn’t in it. She’s not worried by climate change, nuclear war, terrorism, or Brexit. Nor is she worried about where her next meal will come, where she’ll sleep tonight, how she looks, or the future. Nor is she worried about disease or dying. We talk about dying. She’s not bothered by the prospect, and will she even know when death comes close?

So perhaps this is not a bad way to be, perhaps I shouldn’t fret about the possibility of being demented. Will I even know if it creeps over me?

But if offered the choice between dementia soon or death now I think I’d opt for death, although recognising that if that day were to come the drive to keep living whatever would take over?

I’d opt for death for several reasons. I don’t like the idea of being so dependent on others. I don’t want to consume resources for no obvious reason, and I think that meaningful life must give some purpose beyond simply being alive.

I’ve accepted and am even grateful for the knowledge I must die, but I’m not yet ready to be demented. I must keep working at the prospect because there’s a high chance it’s coming.

Richard Smith was the editor of The BMJ until 2004.