BACKGROUND Hyperkinetic disorder or attention-deficit hyperactivity disorder (ADHD) is an important clinical condition.
AIMS The research evidence for a genetic contribution to ADHD is reviewed.
METHOD Measurement of the phenotype, the extent to which attention deficit and hyperactivity are heritable and molecular genetic findings are discussed. Future research directions are also considered.
RESULTS ADHD is a familial disorder. Available adoption evidence suggests genetic influences are important. Twin studies have primarily focused on trait measures which have consistently been found to be highly heritable Molecular genetic studies of clinical disorder so far have suggested the involvement of the dopamine DRD-4 receptor gene and dopamine transporter gene (DAT1). However, these findings await further replication.
CONCLUSIONS Advances in psychiatric genetics and current research interest in the genetics of ADHD should improve our understanding of aetiological factors and have an impact on treatment.