I know I have it because it takes me extreme concentration and willpower to stay still for even a few seconds. Because if I sit still, it drives me crazy. Because I need either Adderall or caffeine to focus on a single task for a long period of time. Before you say placebo, I didn't learn caffeine could have that effect until years after I unknowingly started using it to help me focus. My parents used to bribe me with soda to do my homework, I thought I was focused just off of willpower for years, until I learned I had a stimulant in my system that was helping me. Talk about shitty, thinking you are able to do something yourself only to find out you've had a helping shove the entire time. Oops, I just realized I ranted a bit, sorry about that.