Directions of aetiologic research on attention deficit hyperactivity disorder

Objective: The aim of this paper is to review and integrate recent literature on aetiological factors that have been postulated for attention deficit hyperactivity disorder (ADHD). Method: Recent studies relating to perinatal brain damage, intra-uterine toxic effects, neurochemical, brain imaging and genetic studies are reviewed, and those considered most significant are discussed. Where possible, recent findings are integrated and directions of future research are suggested. Clinical implications are briefly discussed. Results: Perinatal studies indicate that children with a birth weight under 750 g may be disadvantaged for attentional skills. Magnetic resonance imaging (MRI) and steady state visually evoked potential studies show differences in prefrontal, caudate and parietal areas in ADHD children, suggesting right hemispheric dysfunction. Functional MRI studies hold promise in further elucidating attentional systems in the central nervous system that are involved in ADHD. Genetic studies suggest genes related to dopaminergic systems may be important. Conclusions: Recent research on ADHD has made considerable advances, particularly in the areas of brain imaging and genetic studies. Genetic studies should provide further aetiological understandings of ADHD, leading to more targeted treatments.