On a busy stretch on the outskirts of Sydney’s CBD, in an area once famously described as “the conveyor belt of carnage” sits a small plaque that simply reads: “Dr Ray.”

In the heart of the now gentrified Kings Cross, the unassuming memorial pays tribute to Dr Ray Seidler, a man who in his time was something of a local icon; physician to drug addicts, the homeless, sex workers, rock stars and celebrities. He ran his medical practice in Cross’s more notorious era, amid organised crime cartels, red light establishments, strip joints and illegal gambling dens. He did so for decades, while his family maintained a facade of eastern suburbs private school normality. He unravelled so quietly, his suicide in 2013 seemed to come out of nowhere.

“You can usually tell when someone close is on that path, they’re really not very well, they’ve maybe tried before. But with my dad, it really did come out of the blue. And I think that’s a different kind of grief,” Jonathan Seidler, Ray’s son, says.

“I’ve had friends whose fathers have died of cancer, or have had any number of health issues in which there’s been a very slow and often traumatic demise, but the family gets to rally around and deal with it together. We had to do that after the fact. We found ourselves yanked out of our lives in a minute.”

Seidler’s new memoir, It’s a Shame About Ray, is more than a tribute to a father who, in his words, “ate the apple whole; core, pips and all”; who once jabbed steroids into Beyoncé’s butt when she lost her voice just before a sold-out Sydney concert; jumped into Sydney Harbour to retrieve his son’s Power Ranger toy; and took on his teenage kids’ demerit points to the point he lost his own driving licence and had to ride a bicycle to the surgery for a year.

It’s a Shame About Ray is also a story that vivisects a privileged, high-achieving family, with Australia’s most decorated architect Harry Seidler, Seidler’s great-uncle, being the most high-profile member. Seidler pulls at the black seam of mental illness that has threaded its way through generations of firstborn men in his family, and ultimately confronts his own diagnosis of bipolar disorder and the lifelong “chemical padding” he has had to accept to counterbalance the crippling lows with the “superhero” highs.

“If mania is the turbo boost, then depression is the brick wall you slam into at high speed continually,” Seidler writes in his memoir. “If art floats, retains any sense of buoyancy, this is a balm self-applied after the agony stops. It emerges in spite of it, not because of it. I understand that now.”

Seidler believes he inherited bipolar from his grandfather Marcell, Harry’s brother and Ray’s father. Upon receiving his own diagnosis, in the book Seidler muses whether Ray might have regretted giving him the middle name Marcell; naming his firstborn son for a man whose erratic behaviour, serial infidelity and eventual desertion of the family lay the foundation stones for Ray’s lifelong struggles with chronic episodic depression.

One of Seidler’s family homes was a Vaucluse pile, from which the patriarch regularly went awol, only to be discreetly returned by a friendly local cop, hours or sometimes days later. Ray’s absences from work were explained away by his wife and later his adult sons, Seidler and his younger brothers David (now a lawyer) and Zac (a clinical psychologist specialising in men’s mental health). By the time of David’s barmitzvah, the teenage Seidler realised the security guard posted outside his home’s front door at important family functions, to all outward appearances there to prevent gatecrashers, was in fact tasked with ensuring one member of the family stayed in.

“I only really found out what was going on when I was a teenager, and then I realised it had been going on for 10 years,” Seidler says. “But he didn’t talk about it, and we didn’t talk about it. You keep a tight lid on something like that and make sure it doesn’t get out.

“My dad would just be ‘knocked out with the flu’ for weeks at a time … we’d cover off for everyone, his friends, his practice, his speaking engagements. Everybody just dealt with the fact that there was a doctor who was unwell and at no point did anyone, including some of his best friends, actually realise what was going on. As a family, we were so good at hiding it.”

Seidler began writing his memoir while living in London in 2018. It began as a very different book: a work of fiction, inspired by Michael Schur’s hit comedy series The Good Place, which is set in the afterlife.

The early part of the writing ended up as a diversionary chapter of the finished book – an imaginary meeting between Ray and Chester Bennington, the late singer of Linkin Park, the punk-rock band Seidler idolised as a teenager. Bennington killed himself in 2017. Their meeting takes place in the waiting room of an afterlife processing centre for those who have killed themselves.

“My life seems like a cakewalk compared to yours,” Ray tells Bennington.

Chester: “Everyone’s pain is unique to them.”

Ray: “You know, I used to say something similar to my son.”

Chester: “The one who joined our fan club on your credit card?”

Ray: “He was depressed. Said he wanted to kill himself.”

Thirteen-year-old Seidler did rack up hundreds of dollars on his father’s credit card as possibly the world’s most devoted Linkin Park fan, and his suicidal ideation did begin in his early teens.

A close friend read the early passages and told Seidler he wasn’t really writing fiction. He finished writing It’s a Shame About Ray nine months later. But he determined he would not take the step of trying to publish it until he had been given the all clear from the entire Seidler clan.

Of particular concern was the trauma it could reignite in his mother, and his younger sister Zara, who was only 16 when Ray died. Both women had studiously avoided open discussion of Ray’s illness and death within the family in the subsequent decade.

“I was on tenterhooks when my mum was reading it. You give someone a manuscript and you expect that it will take some time for them to get around to reading it. She got it in the morning and she rang me the same afternoon,” Seidler says. “She cried a lot. She said she was proud of me, and said what it would have meant to my dad to have had a book named after him, that dealt with this subject the way it did.”

With a background in music journalism, Seidler’s book unavoidably digresses at times into the world of rock music. In part, It’s a Shame About Ray pays tribute to the artists who travelled with Seidler on his big dipper journey, pre and post diagnosis. When Kanye West revealed his bipolar diagnosis to David Letterman in 2019, it had a profound effect on Seidler. He recalls being 22, tears streaming down his face after receiving his diagnosis, and sitting with his father at the computer to Google “famous people with bipolar disorder”.

What Seidler hopes his reader will take away from the book is a message of hope: a diagnosis of mental illness is not the end of a life, nor does the suicide of a parent have to define you.

“As shattering as it can be for somebody who’s in a family where that happens, it’s not the end of your life,” he says. “I feel like a lot of the literature that I read, particularly when it’s talking about young people, treats suicide like the end of the conversation. There’s insane grief that takes over people’s lives and you never hear or see anything else. Everyone in my family, for better or worse, we’ve all had a second act in our lives. That’s what’s really important.”

• In Australia, the crisis support service Lifeline is 13 11 14. In the US, the National Suicide Prevention Lifeline is 1-800-273-8255. In the UK, Samaritans can be contacted on 116 123. Other international suicide helplines can be found at befrienders.org

• It’s a Shame About Ray by Jonathan Seidler is published by Allen & Unwin ($32.99)