5. Trouble in school
ADHD is a condition that very commonly sticks around a person for most of all of their life, which means someone who struggled with being inattentive and restless during their years in school is quite likely to have carried those same problems with them into adulthood. Adults tend to have the benefit of more discipline to help them work through their ADHD, but the problems can still create many problems no matter how old the sufferer is.