So really noticeable symptoms of ADHD are difficulty paying attention to details, easily distracted by irrelevant things,forgetfulness, inability to sustain attention on tasks or activities, procrastination, often talking excessively, fidgeting, and disorganized work habits. People with ADHD are also very impulsive and often blurt out things, which can take a toll on relationships. Having undiagnosed ADHD can lead to depression and other neurological disorders .