Parents with Inattentive Adhd, ADD and ADHD-PI

I am always curious about the meaning of the findings when I read a study like the study published in the August 2010, Journal of Pediatrics sited below. In this study the researchers found that children with all types of ADHD were more likely to have at least one parent that reported having ADHD.

The study also found that children with a parent that had ADHD had more severe symptoms of ADHD and that fathers with ADHD were more likely to have sons with Combined type ADHD and less likely to have sons with ADHD-PI.

Given that the symptoms of the Combined type of ADHD are generally considered to be more severe than the symptoms of Inattentive ADHD, that men are more likely to have the Combined type of ADHD and that Inattentive ADHD is much less likely to be diagnosed and treated than Combined type ADHD, it is no wonder that fathers with diagnosed Combined type ADHD had sons with diagnosed Combined type ADHD.

It is entirely plausible that mothers and fathers with Inattentive ADHD were simply never diagnosed or treated for Inattentive ADHD and would therefore not report the diagnosis. Confounding this even further is the fact that the symptoms of inattention, unlike the symptom of impulsive behavior, may more rapidly improve with age.

I am not clear whether inattention improves because people with ADHD-PI develop strategies to cope with their inattention or whether the brain develops and improves with regards to attention. It is possible that both these factors play a role. Hyperactivity improves with age and this is thought to be purely the result of brain development.

The Impulsive and inattentive symptoms of the Combined type of ADHD may linger longer. This would make this type of ADHD more likely to be reported in a parental report and more likely to be observed as a contributing factor to an offspring’s symptoms.

For all of these reasons I am skeptical of the findings in this study and I am not sure that this study helps us very much in terms of understanding the role that parental ADHD-PI contributes to the symptoms of children with Inattentive ADHD.

Journal of Pediatric. 2010 August
Parental ADHD Status and its Association with Proband ADHD Subtype and Severity.
Takeda T, Stotesbery K, Power T, Ambrosini PJ, Berrettini W, Hakonarson H, Elia J.
Ryukoku University, Kyoto, Japan; Children's Hospital of Philadelphia.

Abstract

OBJECTIVE: To better understand the familial transmission of attention deficit hyperactivity disorder (ADHD), a highly heritable disorder, the effects of paternal and maternal ADHD status on probands' ADHD symptoms and subtypes were investigated.
STUDY DESIGN: In 323 trios with ADHD, data from a structured interview and a self-report scale (score of >21) were used to determine ADHD probands' diagnostic status and parental ADHD status, respectively. Parental ADHD status on proband ADHD severity and subtypes was investigated.
RESULTS: ADHD criteria were endorsed by 23% of fathers and 27% of mothers, and by at least one parent in 41% of the cases. ADHD severity was higher for children whose parents had ADHD versus those whose parents were without it. Paternal ADHD was associated with an increased likelihood of ADHD combined subtype (odds ratio = 3.56) and a decreased likelihood of the inattentive subtype (odds ratio = 0.34) in male children.
CONCLUSIONS: Parental ADHD status appears to confer different risks for the severity of hyperactive-impulsive and inattentive symptoms depending on parental sex; however, parental ADHD self-report scale score has low to negligible correlation with proband's ADHD severity. Biparental ADHD does not appear to have an additive or synergistic effect on the proband's ADHD severity.