Advances in the genetics of childhood neuropsychiatric disorders over the past decade were reviewed in the literature and reported from Yale University School of Medicine, New Haven, CT. In ADHD a genetic basis is suggested by family and twin studies. A focus on dopamine neurotransmission showed that children with ADHD had a higher incidence of the high-risk variant of DRD4 than controls, but the relationship is still controversial. The dopamine transporter gene (DAT1) has been linked to ADHD. Mice lacking expression of this gene were more active than control littermates. Functional variants of genes involved in dopamine transmission may confer a familial risk for ADHD. [1]

COMMENT. Abstracts of posters presented at the VIIIth World Congress on Psychiatric Genetics, Versailles, France, August 2000, are published in the Aug 7 issue of the American Journal of Medical Genetics 96:452-571. Further evidence of linkage and association between ADHD and DRD4 polymorphism is presented but results were marginal.

Parental ADHD. Weiss M, Hechtman L, and Weiss G provide a clinical perspective on ADHD in parents [2]. ADHD is highly familial. More than 50% of parents with ADHD have a child with ADHD, and 25% of children with ADHD have an ADHD parent. Siblings are frequently affected, and families with multiple ADHD members are especially challenged. Parents with ADHD are recognized for their failure to keep appointments for the child patient, they are restless in the office, they forget to bring along school reports, and they monopolize the interview. Parental ADHD can impact family functioning and the treatment of the child. Family counseling must address both the child’s and parent’s problems.

Executive functions and ADHD are reviewed by Barkley RA in Part 1 of a series of columns on the Genetics of ADHD [3]. The term executive function, deficient in ADHD, includes purposive, goal-directed activity; inhibition of distraction; response inhibition or delayed gratification; selective problem-solving; flexibility; goal persistence; and self-awareness. Self-regulation is essential for normal executive function. The prefrontal cortex is the anatomic localization of these functions. Attention deficits typical of ADHD are termed intention deficits.