ebook_ADHD2019_engl.

The World Federation of ADHD Guide 47 CRITERION C – PERVASIVENESS DSM-5 requires that several ADHD symptoms must be present in at least two different environments. The rationale behind this criterion is to avoid diagnosis in cases where symptoms are manifested in just one environment due to triggers, which are specific to this environment (e.g. ADHD symptoms just at home becau- se of severe family conflicts; or ADHD symptoms just at school owing to excessive demands from the school). However, ADHD is one of the few DSM-5 disorders that require symptoms in multiple settings, and few studies have tested the validity of this criterion. As pointed out by Willcutt, 12 the presence of symptoms in multiple settings is typically based on ratings from two different adults. Because correlations between raters are low-to-medium in magnitude for ADHD symptoms, a lack of agreement on presence of symptoms may simply reflect measurement error and not necessa- rily a true absence of symptoms across settings. Furthermore, some children may display impairment in only one setting at one point in time, but in multiple settings later in development when facing more challenging academic and social demands. Nonetheless, it remains likely that some children who meet symptom criteria for ADHD may exhibit significant impairment that is truly restricted to one setting. This pattern may be especially common in groups with predominantly inattenti- ve ADHD presentation because this symptomatic presentation is associated most strongly with difficulties in academic domains that may be most evident at school. Although the reduction of false positive diagnoses is a goal to be pursued, it is not clear why intervention would not be provided to a child who meets all other crite- ria for ADHD, but significant symptoms are presented in only one setting. CRITERION D – IMPAIRMENT There was a strong debate during the development of DSM-5 around the vali- dity of including impairment as a criterion inside the nosological definition of disorders. In the rest of medicine impairment is more frequently embedded in prognosis than in the core definition of disorders. In addition, ADHD is a highly comorbid disorder in clinical and population samples. This profile poses a special difficulty for clinicians in determining if impairment comes from ADHD or its frequent comorbid conditions. 7 Despite this debate, DSM-5 kept criterion D emphasizing the need for clear in- terference from the symptoms in functioning. Indeed, since ADHD is better con- ceptualized as a dimensional disorder (i.e. symptoms reflect a dimensional trait in