The term "flow" was coined by a psychologist in the early 1990s. It's when you're completely immersed in a difficult activity that you enjoy. You close yourself off from the rest of the world and lose track of time. People with ADHD have a hard time breaking free and shifting their focus to something else.

Screen time appears to be an especially easy way for someone to become hyperfocused. Hours can be spent on video games, television, or social networking.

Hyperfocus can be a blessing and a curse. If you spend hours answering algebraic equations or cleaning the house, no one will notice. However, hyperfocus can lead to interpersonal issues as well as troubles at school or at work.

This can also make diagnosing ADHD more difficult, especially in gifted children. They perform better in school because their high IQs enable them to overcome the learning difficulties that often accompany the disorder, and their capacity to hyperfocus can make it even more difficult to detect.