ADHD is a neurological disorder marked by inattention, impulsiveness, and sometimes hyperactivity. It is more common in boys than girls and symptoms often emerge around age 4. Biological factors like genetics and biochemical imbalances are associated with ADHD. Environmental factors such as prenatal toxic exposure, birth complications, and lead poisoning may also play a role. Diagnosis involves medical evaluation, observation of behaviors, and reports from parents and teachers. Treatment includes stimulant medication, behavioral therapies, education supports, and developing coping strategies.