Attention Deficit Hyperactivity Disorder (ADHD) is a brain disorder commonly observed in children and adolescents. In affected children, it can be seen throughout their life. The symptoms are inability to control anger and emotions, hyperactivity, lacking social skills, cannot able to concentrate and pay attention. As a result, the children with ADHD cannot perform well at school and the behavior of the affected adolescents and adults does not match their age. Though some genetic studies are saying that genes are involved, the exact causes of ADHD have not yet been found. Apart from genes, scientists are focusing on other possible causative factors like surrounding environment, food habits, and injuries in brain. Boys have been diagnosed with ADHD three times more than girls. The treatment for ADHD involves regular counseling, changing lifestyle and timely intake of medicines. In most cases of ADHD, the affected individuals suffer with other relevant disorders that include learning disabilities, Tourette syndrome, oppositional defiant disorder (ODD), conduct disorder (CD), mood disorders, anxiety disorders, obsessive compulsive disorder (OCD), substance use disorders, restless legs syndrome etc. Review articles are the summary of current state of understanding on a particular research topic. They analyse or discuss research previously published by scientist and academicians rather than reporting novel research results. Review article comes in the form of systematic reviews and literature reviews and are a form of secondary literature.