ADHD is a psychiatric behavioral disorder that manifests as a persistent pattern of inattention and / or hyperactivity-impulsivity that is more frequent and severe than is typically observed in individuals at a comparable level of development . The specific etiology of ADHD is unknown and there is no single diagnostic test for this disorder . Adequate diagnosis requires the use of medical and special psychological , educational , and social resources , utilizing diagnostic criteria such as Diagnostic and Statistical Manual of Mental Disorders-IV ( DSM-IVÃ ‚ Â ® ) or International Classification of Diseases 10 ( ICD-10 ) .