In This Special Report:
Over the past century, the syndrome currently referred to as attention-deficit/hyperactivity disorder (ADHD) has been conceptualized in relation to varying cognitive problems including attention, reward response, executive functioning, and other cognitive processes.1 More recently, it has become clear that whereas ADHD is associated at the group level with a range of cognitive impairments, no single cognitive dysfunction characterizes all children with ADHD.2,3 In other words, ADHD is not a one-size-fits-all phenomenon. Patients with this syndrome do not fit into any one category and present with widely differing co-occurring disorders—including varying cognitive profiles.
Thus, ADHD represents not a single disease entity but a heterogeneous group of patients who require differentiated analysis, assessment, and treatment. This article focuses on the cognitive presentation of children (and, to a lesser extent, adults) with ADHD.
DSM-IV specifies that there are 3 subtypes of ADHD:
• Primarily inattentive
• Primarily hyperactive-impulsive
• Combined inattentive and hyperactive-impulsive
Much research has attempted to map particular cognitive problems to particular DSM-IV subtypes but, to date, there has been no consensus. Contemporary neuroscience has helped clarify that cognition and affect are closely related—cognitive computations depend heavily on emotional arousal and valence, just as affective response depends in part on cognitive evaluation.4
The diagnosis of ADHD is not based on cognitive difficulties but rather on evaluation of hallmark behaviors using standardized, nationally validated rating scales as well as a structured clinical interview with the caregiver.5 Cognitive impairments constitute secondary features that often accompany the disorder and need to be considered as part of a comprehensive clinical formulation and multidisciplinary treatment plan. If a child’s cognitive profile is not considered, he or she may respond positively on behavioral ratings to standard treatment (eg, a psychostimulant medication), yet still fail to attain his best academic or social functioning ability because of cognitive impairment.
Cognitive problems and clinical options
The 10 well-established cognitive problems listed in Table 1 should be salient for psychiatric care of ADHD.2 They fall into 2 broad groups: comorbid syndromes and ADHD-related cognitive problems, which are characterized by context-dependent response profiles. These problems are organized by illustrative clinical presentation in Table 2.
It is unknown whether any of the context-dependent cognitive problems are unique to ADHD. However, all appear to be at least partially specific to ADHD because they are not explained by co-occurring psychiatric, behavioral, or learning problems and, in most instances, they are more clearly associated with ADHD (larger effect sizes) than with other disorders.6 Thus, they are part of the established correlates of ADHD at the group level.