Adult coloring books appear to be taking the world by storm. Adults appear to be indulging over geometric patterns, animal designs and gripping landscapes offered by the books. However, the question remains: just what is it with these books that make them so appealing?

It appears publishers are targeting grown-ups who want a new way to relax, clear minds and even cope with different emotions. According to Psychology Today, it's hard to prove if such a concept is a marketing fad given that there is little research on the effect of coloring in the psychology of people. However, experts such as Ben Michaelis said distress comes from external pressures or internal fear of things one can't control. This is why he recommends the same coloring books to some of his clients.

He said that coloring engages them in a "highly-structured" activity that is not goal-oriented. This allows clients to focus on something more manageable and experience less distress.

Even if coloring doesn't help people process negative feelings, according to the Guardian, it does offer an effective form of relief and as an effective method to de-stress. 

The books appear to have less-obvious benefits as well. For instance, an older study in Psychological Science showed that people who took breaks on problem solving by engaging in a "deliberately easy activity" will have increased mind wandering and perform better in subsequent tasks.

According to CNN, this mental pit stop, some in the form of coloring sessions, can help people "de-stress" and set them up for upcoming challenges. Other activities such as repetitive penciling can increase concentration as well. 

The Psychology Today article added that a 2009 study even found out that people who shaded in shapes while listening to a recorded message remembered more details than those who did not. Claire Zedelius, a creativity researcher at the University of California, said coloring may inspire a "relatively mindful state" with some mind watering. 

Either way, coloring appears to be its own reward. Michaelis said that there's an inherent worth in artistic pursuits, as the "act of creating" says there is something inside us that has value. These range from nostalgic feelings to affirmation.