New Zealand researchers say adult colouring books may be more than just a fad - they could improve your mental health.
They've seen an explosion in popularity in recent years with publishers touting their ability to de-stress, reduce anxiety and achieve mindfulness.
But does colouring in actually work?
"We found no documented evidence that this was the case so we thought we'd run a study," says University of Otago researcher Dr Celia Lie.
Study participants were asked to do 10 minutes of colouring in each day, while a second group were given logic puzzles like sudoku and word searches.
"Colouring in over that seven-day period, decreased depressive symptoms and anxiety," says Dr Lie.
Those who did the logic puzzles found no improvement in mood, though both groups saw a small increase in mindfulness.
The adult colouring craze saw books dominate bestseller lists around the world in 2015.
"Every single one of the top 10 in the adult non-fiction was the colouring books at the time," says Booksellers NZ spokeswoman Sarah Forster.
Though it appears they went out of favour just as fast, dropping off the Nielsen Bestsellers List completely.
"I think it was a bit of a fad. And once people had enough of them, I think it got to a point where they no longer needed to buy another because it takes quite a long time to do them."
But perhaps you shouldn't discard them quite yet, researchers say they can be a useful self-help tool.
"You don't have to do great masterpieces of art. Just little small acts of everyday creativity can improve your mood, can make you feel better," says Dr Lie.
Scientists say that like gardening and gourmet cooking, colouring-in can be added to the list of creative activities that help improve our wellbeing.