LEGO was once considered a toy that kids eventually outgrew. But the classic plastic bricks have become a staple for people of all ages, partly because putting them together isn’t just fun—it’s also a great stress reliever.

People have used LEGO to help ease anything from everyday stress to more serious conditions such as post-traumatic stress disorder (PTSD), which is often diagnosed in military veterans. Experts think LEGO might have some of the same benefits as practices like meditation, which help people focus on the present instead of worrying about the past or the future. LEGO kits are challenging enough to be a distraction but not so challenging that they cause more stress. When a person builds a LEGO kit, they concentrate on this fun activity instead of thinking about what is troubling them.

And unlike some hobbies, a LEGO project is also very low risk. The kits come with precise, step-by-step instructions, but users can also experiment and build whatever they want. If a brick is put in the wrong place, it can be moved with no harm done.

“The point is to free your mind of other distractions and focus on play, even if you just have a handful of pieces,” Abbie Headon told the Washington Post in 2020. LEGO, the Danish company that makes the bricks, hired Headon to write a book about the benefits of building with LEGO. Its title is Build Yourself Happy: The Joy of LEGO Play.

With so many people reporting the benefits of LEGO, scientists are beginning to look for evidence—and finding it. In one recent study, using LEGO had a positive effect on stressed-out adults. Another study found that using LEGO can improve communication and social skills in children.