Why do people with hyperactive ADHD symptoms fidget and have trouble sitting still? Why are people with any ADHD symptoms at all often drawn immediately to the most interesting and stimulating activity available, even when it’s against their long-term interests?

BrainOne possible answer is that these behaviors are ways of “waking up” the ADHD brain.

If you have ADHD, you aren’t necessarily going to contest the idea that the ADHD brain is in need of a good waking up. In general terms, the theory goes that people with ADHD have brains that are constantly in a state of low arousal.

This inability of the ADHD brain to self-regulate in order to keep itself at an optimal energy level could lead in turn to a lack of vigilance and attention, and a profound dislike for understimulating tasks – if your brain is already hungry for stimulation, the last thing it wants is a day of filling out taxes, organizing your desk, and taking care of the laundry.

By contrast, behaviors like fidgeting or gravitating to the most rewarding activity in reach (even if it’s not necessarily the one you should be doing) could be interpreted as attempts to “wake up” the ADHD brain, to increase its level of arousal. If the ADHD brain can’t regulate its own energy levels, it makes sense that it might look for stimulation from external sources, like physical movement and rewarding activities.

This picture may be oversimplified – the brain is complicated, so this probably isn’t the full story of what ADHD is. But the research does suggest that underarousal may be a key part of ADHD. Most recently, an EEG study from researchers in Germany showed that people with ADHD tend to have lower levels of brain arousal overall, as well as more inconsistent and unstable levels of brain arousal.

From the outside, it may seem like a paradox that someone with ADHD both apparently lacks the energy necessary to stay focused and motivated yet also has the energy to be fidgeting up a storm and impulsively pursuing new activities. But if you think about it in terms of arousal levels, this “paradox” starts to make more sense. The ADHDer in question may be fidgeting relentlessly and acting on impulse in order to compensate for the lack of stimulation that makes it hard for them to pay attention – that is, in order to wake their brain up through external stimulation.

Image: Flickr/El Neato