Rummaging in the attic, a cardboard box nonchalantly labelled as ‘Stuff’ bursts with the colouring books of my childhood. I have fond memories of sitting around a dimly lit kitchen in the middle of winter with my brothers, colouring in images of robins with ribbons streaming out of their beaks, or watching The Little Mermaid in my classroom as the rain trickled outside. Most if not all of the images in these colouring books are defiled with colour: flamboyant pinks that burst out of the outline, and smiling dolphins erratically shaded with a strange concoction of greens and oranges. Their pages are weary with soda stains and smudged fingerprints, yellowing with age and confined since the 90s to a box in the darkness where we store all the remnants of youth.

It was a strange sight, then, to discover my friend’s collection of colouring books, lined up and illuminated upon a shelf in her room. Flicking through, the designs were beautiful and elaborate: an intricate labyrinth made of flowers, a peacock bedecked in nature, his feathers leering across the page and morphing into swirling vines. The colours were ordered and fresh, and it took me a while to gather that they had been shaded only recently with the small, delicate box of colouring pencils laying on the shelf beside them.

Wired on a shameless volume of black coffee, bleary eyed from staring at a screen all day, and fretting about the books piling up upon my desk, I sceptically borrowed one – Johanna Basford’s best-selling Secret Garden – imagining it lost in the whirlwind of papers disordering my desk. After receiving numerous badgering messages asking if I had tried it yet, I begrudgingly grabbed a few colouring pencils before bed one evening, wondering how much progress I could have made with my essay during this time. Strangely, the anxiety dissolved as I concentrated upon the image before me, shading the forest scene and slowly colouring it into life. I felt a sense of order and agency, things that had been rattled by the onset of a Cambridge degree, characterised by the flurry of academic and social commitments that sweep you up and do not let go. I began to feel slightly insane, my pride in my sceptical, logical nature challenged by ‘mindfulness’, that pseudo-psychological buzzword.

Yet the type of artistic expression that is found in adult colouring books is very much a popular therapeutic technique. ‘Art therapy’ is utilised in response to various modes of emotional trauma and medical conditions, from cancer patients to bereaved or orphaned children; art becomes a vehicle of expression and communication, giving a medium to individuals through which they can cope with stress and trauma, and encourage a sense of achievement. Improvement in cognitive abilities and memory capacity have also been concluded, and ‘art therapists’ must be registered and licensed with the Health and Care Professions Council to practise.

Even as the adult colouring book market has soared by joining the ‘mindfulness’ craze (Cambridge is even offering ‘mindfulness’ classes as part of its counselling service this term), it has also contributed to the surge in interest for items of nostalgia, aptly named the ‘Peter Pan’ market. Adult colouring books occupy a strange line between ‘mindfulness’, which involves a complete relinquishing to the present moment, and this new market for childhood experiences, a regression back into an emotional state of the past. Adult-only summer camps in the USA are burgeoning, and East London’s wacky ‘Cereal Killer Café’ tempts with sugar-laden children’s cereal reminiscent of a Monday morning before school.

After half an hour of colouring orchids and butterflies deep shades of pretty purples and delicate blues, I slept quietly, without being awoken by rushing thoughts of deadlines or the constant, anxious turning of my body. Whether the result of a self-induced ‘mindfulness’ session, or the outcome of simply tearing myself away from the multiplicity of glowing screens that make up my daily life, the popularity of adult colouring books is a material outcome of the buzzing anxiety that lies concealed and unnamed in modern society.

Perhaps in a decade or two I will wistfully look back upon these books, but instead of seeing Ariel’s fiery mane and hearing the drip of the rain, I will remember the smothering pressures of my adult life between the velvet green leaves.