When I think of the women who share my diagnosis, I always come back to Katharina. Maybe it’s because we both have an iteration of the same name or because we ache for answers to an illness that is little understood. Yet it’s funny, too, that I think of her so often, considering the account of her life is not in her own words but is a 10-page case summary in Sigmund Freud and Josef Breuer’s Studies on Hysteria. A “sulky-looking girl of perhaps eighteen”, Katharina approaches Freud in the late 1800s while he’s holidaying and asks him for help. She is unwell, she says, recounting her illness: “It comes over me all at once. My head gets so heavy, there’s a dreadful buzzing, and I feel so giddy that I almost fall over. Then there’s something crushing my chest so that I can’t get my breath.” Katharina says during this, “I always think I am going to die”.

Despite Freud’s description of Katharina as meek, I see myself in her. I understand what it is to experience visions, to fear what is happening within your body. When I am ill, I see white dots or washes of colour. My body numbs, temperature drops. Sound turns down and I am faced by people’s moving lips. I cannot quite speak and sometimes, pain shoots down behind my left eye. I am not only hurting but disconnected. The world and the people around me feel further away than ever.

Freud diagnosed Katharina with “acquired hysteria”. Two hundred years earlier, Mary Glover – another woman whose life I fall into – was diagnosed with “hysterico passico”. And three years ago, I was told I was experiencing the same: now known as psychogenic non-epileptic seizures (later, I’ll learn this is also called functional neurological disorder or sometimes, still, the old-fashioned term coined by Freud, conversion disorder). Despite the changing names, the meaning has remained; each diagnosis is one long iteration of the term “hysteria”. It’s categorised as a mental illness in the Diagnostic and Statistical Manual of Mental Disorders (DSM V) and I consider it as one through my own experience of treatment. Yet so much is unknown, and definitions are murky. Personally, I think this illness is not a diagnosis but a lack of one.

When Mary was thought to be possessed in London in 1602, she underwent an exorcism where she said, “Strengthen me, O Lord, against that Goliath”. I think of this idea of illness as a Goliath often, despite my lifelong atheism. But, for me, illness is a Goliath you cannot beat. It is a part of me. It is something to live with, sometimes in anger, or in acceptance; it is a Goliath I know intimately.

Reading the nuances of Katharina and Mary’s experiences has kept me hopeful in my ability to keep going. To be “brave as a rule” like Katharina describes herself to Freud. With Mary and through reading her words as recounted by the priest who sat by her side during the exorcism, which brought out the worst of her illness, I see myself reflected in her fear, her desperation to do anything to be well once again. I’d like to think I also see myself in the dignity she holds on to throughout a terrifying process. Like Mary, during my own diagnosis I didn’t know what would happen next, nor if I could ever live with independence once again.

I read about Katharina and Mary and two other women, Edith and Blanche, for my forthcoming book, Hysteria: A Memoir of Illness, Strength and Women’s Stories Throughout History. Reading their lives made me feel as if I was not alone; instead, I was a link in the history of powerful women who advocated for themselves, who experienced illness, who were helped and harmed and objectified by the medical profession. The connection to something bigger kept me afloat; it kept me writing so that I, too, could become a small piece in the story of ill women.

Yet, the process of research and writing was as shattering as it was empowering. Only one of the women I researched wrote about herself. I learned a lot from reading about Katharina and Mary, but I was always reading in-between the lines of the men who transcribed their illness. And while it hurts to read about their pain, worse still is knowing what isn’t written. The mistreatment, the lack of understanding. I often think of the women whose stories weren’t privileged and how they were treated – or rather, lived without treatment.

It’s these little slivers of stories that allow me to piece together a history of women within my own experience. To have something quickly change in your body can be alienating. It’s easy to feel like the other. For me, this feeling of unbelonging is on par with the discomfort of the symptoms themselves. But tapping into the history of other women’s mental illness histories has allowed me to feel connected. I am one of them, working and agitating towards understanding and care during treatment. Reading their stories, I see them and feel seen myself; I am their fear and resilience and hope.

• Katerina Bryant is a writer based in South Australia. Her first book, Hysteria: A Memoir of Illness, Strength and Women’s Stories Throughout History, will be published by NewSouth on 1 September 2020