Do hyperactive symptoms matter in ADHD-I restricted phenotype?

The objective of the current study was to evaluate a proposed restrictive inattentive type of Attention Deficit Hyperactivity Disorder (ADHD) by comparing clinical correlates among youths with ADHD inattentive type (ADHD-I) as a function of the number of hyperactivity symptoms presented (none vs. 3 or less) and controls (individuals without ADHD). The sample for this community-based study was comprised of youths aged 6 to 18 years from 12 public schools in Porto Alegre, Brazil. ADHD-I groups had lower levels of adaptive functioning (p < .001) and a higher occurrence of familial ADHD (p < .001) when compared with the controls. There was no significant difference between the two ADHD-I groups. Also, both ADHD-I groups had higher rates of oppositional defiant disorder than controls (p < .001) without significant difference between them. For generalized anxiety disorder and social phobia, only the ADHD-I without HI group showed significant differences compared to controls.