Worrying, as Francis O’Gorman shows in this refreshingly unconventional history, is a hard activity to pin down. Undoubtedly distressing for those who do it, but rarely classed as a pathology requiring therapy or medication, fretting often intrudes when we are doing other things. It is, as he puts it, a “woodpecker-like tapping away at one’s day from inside the unobservable parts of the mind”. Being mostly secretive, slightly shameful and a complete waste of time, its niggling persistence is only finally resolved in death, when “the long list of hidden fears and troubles with which we have been negotiating all our life enters oblivion”.

O’Gorman’s is a brave choice of topic in other ways. A virtuoso worrier himself – his favourite word is “but” – he is sorely aware that, when put into words, worry can be “remorselessly uninteresting”. When he writes in his preface that his unrelenting anxiety, on a recent trip to Venice, “poisoned the prosecco, soured the sarde in saor”, he has already, of course, anticipated how an unkind reader might react. Most of our worries, like this one, can be filed under that well-used Twitter hashtag, “first world problems”. Worrying can seem self-indulgent, embarrassing and irrational. Every worrier will feel a twinge of recognition at Roger Hargreaves’s Mr Worry, who has his worries removed by a wizard and then worries about having nothing to worry about.

A professor of English, O’Gorman has produced a scholarly monograph but a more freewheeling piece of creative scholarship. He hasn’t entirely cured himself of that academic tic that, instead of getting on with the argument, ceaselessly sets out its terms: “I want to move away from a straightforward notion … I want to begin to search out what it is we think we know of another person … ” It makes for a circuitous read, especially since, as he notes, “worry doesn’t have good synonyms”. No other word will quite do, so it and its derivatives end up peppering every page. He also has a distracting habit of oddly compressing words (“I know there’re two things … ”), perhaps in an effort to leaven the density of the book’s argument and make it more conversational.

Once you get used to it, though, it becomes clear that O’Gorman has managed a rather felicitous marriage of theme and form. For he worries away about worrying, and mimics in his narrative’s style and structure what he describes as “fretfulness’s habit of returning, its circularity, its refusal to be put off with an answer”. At its best, O’Gorman’s riffing becomes a way of exploring wider questions about life, the self and being human. It helps that worriers have butterfly minds. We are terrible prioritisers who cannot distinguish between big and little problems, so a low-level squeak of unease about whether we have locked the back door can easily segue into a full-on existential crisis.

According to the book’s loose-fitting chronology, worrying, which at first referred solely to the act of choking or distressing animals or humans, acquired its more common modern sense in the 19th century. It was “the unhappy child of a turn from the Gods to man”, born as we shifted from a belief in predestination and omnipotent deities to reasoned thought as the best way of making sense of a life. And yet worrying, a form of superstition that secretly traded in charms and fetishes to ward off misfortune, was also evidence of the survival of pre-modern beliefs. For every worrier feels that worrying somehow helps, that if we desist from it we will be punished for our complacency. We act, in O’Gorman’s words, as if trying to win the favour of invisible forces, “to placate great and dangerous Gods that have no names, no forms of communication, and very little mercy”.

Alongside this sort-of history, O’Gorman sprinkles his book with neat little insights. Worrying about other people can be, he writes shrewdly, “an easier kind of ‘love’”, a form of insecurity about letting go of and accepting the otherness of others. Worriers like to enjoy things retrospectively, for worrying’s momentum is solely future-directed and the one thing it cannot touch is the past. “Now it’s over,” as he writes after returning from Venice, “I can sit back and enjoy my holiday.” He also recommends a vegetarian diet for worriers because it “reduces the epic struggle of menu reading”, and suggests that losing one’s smartphone is especially disquieting for the modern-day worrier because “such technology is bound up with reassurance, with things that promise security and connection”.

The best parts of this book, as you would hope from a literary critic, are the textual readings. O’Gorman doesn’t just provide illuminating discussions of worry literature – the way, for instance, that the modernist novel embodies the experience of worrying in its interior monologues and cyclical, diurnal plotlines. He also reads worry per se as a literary trope, a “comedy of mental manners” in which its victims are like stage characters trapped in their humours, always enacting the same scenes and parroting the same catchphrases. He is often dryly funny himself. “Worriers can rarely be calmed by a mere statement of the opposite,” he writes, “which is a pity, since it is a staple technique of the non-worrier’s advice to the worrier.”

An argument begins to emerge about the value of a pragmatic pessimism as a corrective to the bland, deluded optimism of the contemporary happiness and wellbeing industry, with its self-help guides and training courses that urge us worriers simply to take on new, more rational beliefs and learn to deal with our anxiety, anger, depression or stress. O’Gorman sees this collective mental landscape as a direct descendant of the liberal rationalism of Victorian philosophers such as John Stuart Mill, who believed that happiness would result from “well-mannered debate, the exercise of a grown-up human being’s capacity to reason”. In our secular liberal world, which puts such value on rational choices, consumer freedoms and complete ownership over our life decisions, worry – “a kind of mental risk assessment gone wrong”, as O’Gorman nicely has it – is far more likely to fester and flourish.

While this is defiantly not a self-help book, it offers up some modest advice and solace for the worrier. Worriers, it suggests, have a salutary sense of “the unconsoled ridiculousness of human life”. They can be creative thinkers, “philosophers-in-ordinary” who see fresh angles or loopholes that others have missed. Don’t come to a worrier for a decision, it warns; but they are rather good at setting out the parameters within which decisions can be made. For O’Gorman, it is not the pursuit of reason, nor the retuning of our habits of mind promised by cognitive behavioural therapy, but art – and especially for him, as a former organ scholar, Bach – that affords the best way out of the worrier’s exhausting self-examinations. Art is the antithesis of worry, for it works through structures and forms that are utterly unlike our cluttered and hyperactive minds.

While it failed to assuage any of my worries, this winning little book still made me root for and, yes, worry a little for its author. I hope this review stops him fretting for a bit, at least until the next worry arrives.

• Joe Moran’s book Shrinking Violets: A Secret Life of Shyness will be published next year. To order Worrying go to bookshop.theguardian.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min p&p of £1.99.