Neuropsychological assessment for the differential diagnosis of Attention Deficit / Hyperactivity Disorder (AD/HD)

Abstract

Attention Deficit/Hyperactivity Disorder (AD/HD) is a neurodevelopmental disorder present from childhood and often following individuals into adulthood. It is the most frequent reason for referring children to mental health services. Core symptoms of AD/HD (inattention, impulsivity, hyperactivity) present behaviors that parents may rate in standardized questionnaires (e.g., does not study, memory problems, cannot concentrate, cannot stay still, has no motives, etc.), are also present in other developmental or psychiatric disorders (e.g., specific learning difficulties, sensory modulation disorder, mood or anxiety disorders, autistic spectrum disorders). This may cause errors in the differential diagnosis if clinicians do not add objective measures of cognitive deficits associated with each disorder. AD/HD presents neuropsychological deficits (compared to non-clinical populations) that are also present in other disorders, like deficient working memory, whereas other neuropsychological deficits are unique characteristics of AD/HD, such as sustained attention, response inhibition, and variability of response time. Likewise, anxiety disorders present neuropsychological deficits in autobiographical memory, mood disorders present neuropsychological deficits in processing speed and verbal memory. Neuropsychological tests such as the Continuous Performance Test, tests of reading phonetic decoding, and others, may improve the accuracy of differential diagnosis, differentiating AD/HD from other disorders, or revealing the comorbidity of AD/HD with other disorders.