[What is child attention deficit hyperactivity disorder?].

Prevalence of attention deficit hyperactivity disorder (ADHD) is around 5%. The main clinical criteria of ADHD are hyperactivity, impulsivity and attention deficit. Several clinical patterns are described. ADHD symptomatology change with age but always start before 7 years old. Comorbidity is frequent and it is important to distinguish ADHD and another differential diagnostic. Disorder mechanism is complex and associate several factors mainly neurobiologicals and genetics. For diagnostic, we use a clinical approach. Some questionnaires, cognitive and attentional tests can help for. It is important to take into account parent, child, caregiver and professor observations. Developmental evaluation is necessary for diagnostic and therapeutic strategy.