STAND-up comedy requires a kind of courage that few of us possess. Susan Calman, who came to comedy from the unlikely starting point of corporate law, clearly doesn’t lack personal fortitude. In Cheer up Love, however, she has found something even more challenging than the slings and arrows of alcohol-fuelled audiences in darkened rooms. This is a testimony of one woman’s battle with depression or, as Calman terms it, the Crab of Hate.

Like Churchill’s Black Dog, the Crab of Hate follows Calman everywhere she goes. She was a self-harmer or, as she says in her searing comedy routines, “a cutter”, which “is blunt, in your face and cannot be misconstrued as anything other than what it is.”

Sectioned at sixteen, Calman was sent to an adolescent psychiatric hospital in Glasgow which she shared with “some incredibly disturbed people”. That experience taught her to pretend that everything was fine so that she wouldn’t have to go back.

Calman stares down her Crab of Hate with unblinking honesty. The book is called Cheer up Love because it’s one of the worst things you can say to someone who is depressed. There are lots more things you shouldn’t say, including “it could be worse”, “pull yourself together” and “at least you don’t have cancer”. The list of things you should say is much shorter, but equally instructive. It consists of variations on being present, listening, working together and emphasising a person’s importance.

The book is written in the form of an extended, first-person comedy sketch on a serious subject. Initially, the paradox is slightly awkward as Calman tries to find a balance between talking about her depression, joking and quoting formal passages from the Mental Health Federation. But she is highly skilled and soon blends personal experience with amusing anecdote and good advice.

Take, for instance, her search for a therapist. She met the first one “in a room [that] smelled of Shake n’ Vak and despair”. Calman was told to draw and sketched a cat and a duck. The therapist informed her that she was a duck that really wanted to be the cat and was expressing her alienation from society. Another therapist clearly misunderstood the therapeutic process and was annoyed with Calman “for not asking me how I am or what’s going on with me.”

Eventually she finds the right therapist for her, and points up the importance of being an active participant in one’s own recovery. Perseverance is a close cousin to courage and Calman has that too. It’s striking how often she refused to give up; including in her personal life where, after a series of disastrous dates arranged through personal ads, she found the woman who is now her wife.

This is a book that everyone should read, and not only because it makes a serious issue both engaging and instructive. The effect it had on my own awareness of mental health issues was immediate. Between starting and finishing it, I noticed a number of stories related to mental health that I might otherwise have missed; including a former Scotland rugby international who publicly addressed his own battle with depression and a plea by Margaret Trudeau, mother of Canada’s Prime Minister, for an end to the stigma surrounding mental health.

Sadly, those who most need to read this book probably won’t. Calman prefers to call the treatment she has received on social media “bullying” (which is what it is) rather than use the more innocuous term “trolling”. Some years ago, she had an epiphany during a show when a man, dressed appropriately enough as a penis, yelled out “I kill fat dykes”. She walked off stage and decided to eschew insult-based comedy in favour of the personal, honest and emotional. This transformed her career but couldn’t protect her from men dressed as penises sitting in front of laptops. The advice given to her on how to deal with online abuse included come off Twitter, develop a thicker skin or just ignore it. All this, she says, “fails to understand how personal it can be”.

The last line of the book channels Helen Reddy and the theme song of the United Nations’ Year of the Woman in 1975: “I am Calman, hear me roar”.

Perhaps some of those still out of earshot will read her story. There’s potential for repentance in it as well as instruction, entertainment, courage, and integrity.

Cheer up Love: Adventures in Depression with the Crab of Hate by Susan Calman, is published by Two Roads, priced £16.99.