ADHD risk alleles associated with opiate addiction: Study of addicted parents and their children

Background: Polymorphisms in genes such as DAT1, 5HTTLPR, D4DR4, and MAO-A have been linked to attention deficit hyperactivity disorder (ADHD) and susceptibility for opiate addiction. We investigated in opiate-addicted parents and their children the rate of ADHD and genetic markers that could predict susceptibility to ADHD and/or opiate addiction. Methods: We studied 64 heroin-addicted, methadone-maintained parents, and their 94 children who had or had not been exposed prenatally to opiates. DNA extracted from mouthwash was assessed for genetic polymorphism for six polymorphic sites of four different genes. Study subjects also filled a variety of questionnaires assessing the rate of ADHD in the parents and children and the children's intelligence quotient. Results: Children of opiate-dependent mothers had a higher rate of ADHD compared to those of the opiate-dependent fathers. Opiate-dependent parents have a high risk of being carriers of most risk alleles examined except DRD4EX3 (allele 7). There was no difference whether the addicted parents had or did not have ADHD. Conclusions: Serotonergic and dopaminergic risk alleles seem to be mainly related to opiate dependence with no effect on the occurrence of ADHD. People carrying those polymorphisms are susceptible to opioid addiction and not necessarily to ADHD.