[Attention deficit hyperactivity disorder (ADHD) in preschoolers: nature, assessment and treatment]

Attention deficit hyperactivity disorder (ADHD) is the most frequently diagnosed behaviour problem in school-age children. Although more and more preschool-age children are referred in clinical settings for typical ADHD symptoms, few studies have examined the nature, the assessment as well as the treatment of ADHD in this age group. This literature review addresses the nature, the assessment, and the treatment of ADHD during the preschool period. The main themes reviewed are: prevalence, symptomatology, etiology, comorbidity, consequences on normal development and adaptation of the child, evolution of symptoms from preschool to school period, difficulties related to diagnosis, assessment modalities, psychosocial treatment, and pharmacological treatment.