Background: ADHD is highly prevalent, characterized by age inappropriate levels of inattention, hyperactivity and impulsiveness. It represents a substantial threat to healthy social and academic development, and increased risk for psychiatric comorbidity. Knowledge about early characteristics, developmental trajectories, and risk factors is still scarce. Early diagnosis and intervention might prevent unhealthy development, but there are no criteria or methods to help identify ADHD in preschool age.
Aims: Describe early characteristics and natural trajectories of ADHD symptoms in children aged 36-44 months. Investigate etiological factors and identify risk- and protective factors for the development of ADHD and comorbid conditions.
Method: A prospective fo llow-up design including a clinical case-control design is followed. Children recruited from the Norwegian Mother and Child Cohort Study (MoBa) are invited to a one-day clinical examination, with child psychiatric assessment, neuropsychological and neurom otor assessment, and structured parent-child interaction. Children (n=1200) scoring high on ADHD-related questions in the 36-mo MoBa questionnaire and randomly selected children (n=400) are included. On all children in MoBa there is information about preg nancy, birth, diseases, mental health and development collected at 6, 18, and 36 months, and blood samples from mother, father, and child. A follow-up is planned for the next MoBa questionnaire at age 7-8 years, with similar clinical assessment.
Scientifi c impact: The large group of clinically assessed children with rich prospective information and biological samples represents a unique data base for investigating important scientific problems related to ADHD. The study will provide knowledge necessary fo r early and precise identification of children at risk for developing ADHD, and knowledge about etiological factors necessary for developing programmes for effective preventive and remedial actions and treatments