ebook_ADHD2019_engl.

The World Federation of ADHD Guide 117 Young children in pre-school years tend to present more hyperactive symptoms since attentional demands are not yet high. In school age children, we see more frequently the combination of symptoms in both dimensions. Hyperactivity tends to decrease during development. Thus, a child who was extremely hyperactive/ impulsive in the pre-school years could present with a combination of attention problems and hyperactivity in school years and then might turn out as an adoles- cent/ young adult with predominantly inattentive problems and executive deficits. 5 Interestingly, there is a gender effect in the manifestation of symptoms. Fe- males tend to present more inattentive than hyperactive symptoms. Boys tend to present more hyperactive or a combined profile of symptoms. Since hyperactive and impulsive symptoms tend to cause more visible impairments, ADHD tends to be recognized more in males. A common doubt parents have is how symptoms so different as inattention and hyperactivity might be part of the same disorder. The brain mechanisms related to the disorder suggest that deficits of inhibitory control are essential in the disorder, although not the unique mechanism. Thus, if the brain areas responsible for “our Figure 6.2 Prevalence of ADHD in different studies according to their date of publication. Each point represents the frequency of ADHD in a given study. The solid line represents the predicted mean prevalence for each year across the 3 decades. The dashed lines represent the 95% confidence interval bounds). From: Polanczyk et al. 13 Permission granted by Oxford University Press. Reproduction prohibited. 20.0 10.0 5.0 2.0 1.0 0.5 0.2 0.1 1985 1990 1995 2000 2005 2010 Year Prevalence estimate