ADHD is called attention deficit hyperactivity disorder, this is caused by a chemical imbalance in the patients brain, (they also have lower dopamine levels), and studies have found its the way neurotransmitters work in the brain as well. This causes patients to have a shorter attention span, emotion management, trouble with fidgeting, impulsiveness, mood swings, absent mindedness, forgetfulness, and many more, affecting day to day life. Please don’t self diagnose as it is a difficult thing to deal with, i have been diagnosed with it and take medicine for it everyday.