I was in my late teens when my brother was diagnosed with schizophrenia. The exact process was never explained to me, but I assumed it involved something very precise: a blood test, a brain scan, something involving detailed charts and numbers. The label was so frightening — the medication so powerful, the prognosis so dismal — that it seemed inconceivable that the diagnosis rested on observations alone. Yet it did. Thirty years down the line — same label, same drugs, same prognosis — it is harder than ever to recall how things were before.

For years, I didn’t read anything about schizophrenia, though I’d often get angry with people if I felt they were “showing ignorance” about the condition. “Showing ignorance” could have meant mocking or stereotyping sufferers, but it could also (if I’m honest) have meant just asking questions. I had some sense that there was a thread at which I didn’t want to start pulling. I knew that if I started thinking about the illness itself, I might end up thinking about the treatment and the irrevocable damage it was causing. The two have always been bound together in my mind: no one would do this if they didn’t have good reason. And: now it’s been done, it is impermissible to imagine things could have been any different.

If you allow the treatment to define the severity of a psychiatric illness, it is easier to witness what years on high-strength antipsychotics can do to a person’s physical and cognitive function. If, on the other hand, you allow for a degree of uncertainty, doubts can start to plague you. Mental illness fatalism can be a coping mechanism, for sufferers and carers alike. If nothing can ever get better, nothing you are doing could be making it worse.

I am not convinced this new way is more respectful of sufferers

In her 2013 book The Bitterest Pills, psychiatrist Joanna Moncrieff explores the way in which drug-based treatments for schizophrenia helped to solidify the belief that this was a defined condition that required these self-same treatments. She describes “a self-perpetuating cycle, with the illness model of mental disturbance justified by the disease-centred model of drug action, which was itself bolstered by the idea that mental disorders are properly thought of as discrete, biologically-based ‘diseases’”. Within this cycle, the impact that the drugs have on sufferers must necessarily be considered less than the impact the illness would otherwise have — even if the former might include brain shrinkage and a lower life expectancy.

I write this not necessarily to question the rights or wrongs of current treatment pathways, but to note that how we understand severe mental illness, and how sufferers and carers are forced to relate to it, can be shaped by what is considered an “acceptable” response to it. Once certain decisions have been made, and particular steps already taken, there is an incentive to insist we know more than we actually do — and that things were definitely more hopeless than we can possibly know them to have been. As Carol Tavris and Elliot Anderson write in their study of cognitive dissonance, Mistakes were made (but not by me), “people become more certain they are right about something they just did if they can’t undo it”.

This is one of the things that frightens me about Canada’s plans to make medical assistance in dying available to people whose sole medical condition is mental illness. It is not because I underestimate the pain that might drive a person to request this, but because it would force us to change, yet again, our understanding of what diseases such as schizophrenia are. It would create an even stronger necessity to pretend we know more than we do, not about suffering, but about hope. No one would help you to kill yourself unless they were sure this was the only option. To have that degree of certainty, there are possibilities that would have to be discounted forever.

In a BBC article on euthanasia, Canadian doctor Madeline Li describes the first time she helped someone to die:

It was like stepping off a cliff, that first one. Then time passes and it normalises.

This was a patient with ovarian cancer, which kills around 1,950 Canadian women each year. Mental illness is not like ovarian cancer. I am conscious that in claiming this I may be seen as trivialising the former or stigmatising sufferers. The trouble is, I know my own idea of “validating” my brother’s illness used to involve never thinking about the ways in which it differed from diseases such as cancer. I could persuade myself I was taking the diagnosis seriously, but I was also ensuring I never had to feel complicit in all that his treatment took from him.

“Validating” someone else’s suffering can transform it into something self-contained, inevitable, nothing to do with you. It is not virtuous to pretend that we know — at least not with absolute certainty — that some states of mind necessitate the destruction of healthy bodies. It isn’t true when it happens in slow motion, over the course of decades, and it’s not true if it happens over the course of a day.

Assisted dying on the basis of mental illness forces us to think about mental illness in a new way forever, simply in order to live with ourselves. I am not convinced that this new way is more compassionate or respectful of sufferers. “Psychiatry’s greatest sin,” writes Richard P. Bentall, “has been to crush hope in those it has claimed to care for. Without hope the struggle for survival seems pointless.” Hopelessness might be exonerating, but it cannot be the best we have to offer those most in need.