The symptoms could mimic other disorders and not necessarily ADHD. There is no one way to diagnose ADHD though, not even all psychiatrists and psychologists can spot them easily that's why it is so important to find someone who specializes with ADHD. There are a lot of resources online about it and you can look into them. I guess the most important thing to remember when considering ADHD is that the symptoms should be present since childhood since it is an inborn condition.