Molecular genetics of ADHD: prospects for novel therapies.

Attention deficit hyperactivity disorder has been shown to be a highly heritable disorder, leading to an increasing interest in genetic studies. While multiple genes may be involved, the candidate gene approach is based on postulated neurotransmitter mechanisms. Molecular genetic advances in relation to dopaminergic (dopamine transporter, dopamine D4 receptor and dopamine D5 receptor) genes, adrenergic, serotonergic and nicotinic receptor genes are reviewed. Comorbidity of attention deficit hyperactivity disorder with learning disability is discussed and possible genetic influences briefly reviewed. Recent pharmacogenomic studies of ADHD are reviewed and promising pathways suggested. Treatments 5 years from now may be more individually tailored in terms of gene/phenotype relationships.