The genetics of ADHD and substance use disorders

抄録

Attention deficit-hyperactivity disorder (ADHD) is a neuropsychiatric disorder with an average heritability estimated around 76%. Individuals whose ADHD persists into adulthood have approximately 50% of the lifetime risk to develop any SUD co-morbidity and patients with SUD present a higher prevalence of ADHD than general population. This link between ADHD and SUDs has been documented in family members of both adults and children with ADHD. Despite this high incidence of SUD in subjects with ADHD and the studies that consistently show genetic basis for the overlap, little is known about the specific genetic factors that could be involved in the development of both disorders. Until today, research has mainly focused on candidate genes of the dopamine, serotonin, norepinephrin neurotransmitter systems, or SNARE complexe. Among the most vulnerable patients with ADHD to develop SUD later in life are those who have co-morbid CD or ODD and evidence suggest that co-occurrence of symptoms for ADHD and CD contribute in an epistatic manner to a more severe form of SUD than individuals with ADHD or CD alone. Most recently, there is growing interest in studying the potential role of post-transcriptional regulatory elements in the susceptibility to different complex disorders. It will be presented the results of the first case-control association study in ADHD that evaluate the role of SNPs within miRNAs or miRNA target sites and, thus, with a potential involvement in the modulation of the miRNA-mediated gene expression. Finally, new data about the genetic relationship between ADHD and cannabis dependence will be presented.