Attention-Deficit/Hyperactivity Disorder (ADHD) is a common childhood behavioural disorder -- systematic reviews demonstrate that the community prevalence of ADHD worldwide is between 2% to 7%, with an average of around 5%. Additionally, a Additional 5 percent of kids have significant issues with over-activity, inattention and impulsivity that are only sub-threshold to meet full diagnostic criteria for ADHD. Estimates of the administrative (clinically accepted and/or documented ) prevalence vary worldwide and although rising over the years, ADHD remains relatively under-recognised and under-diagnosed in many countries, especially in women and older kids. The timely recognition and treatment of children with ADHD-type difficulties provides a chance to improve their long-term outcomes. This review includes a systematic review of the community and administrative prevalence of ADHD in children and adolescents; an overview of the obstacles to accessing care for ADHD; a description of prices connected with ADHD; along with a broad discussion of evidence- based pathways for the delivery of clinical care, such as a focus on key issues for just two specific age groups - preschool children and adolescents requiring transition of care from kid to adult services.