Cognitive functions of adults with ADHD: a neuropsychological examination in a clinical referral context

Neuropsychological functions are important for our daily life, such as being alert and focused, planning ahead, setting and prioritizing goals, and selecting, storing, and retrieving information from our memory. Adults with attention-deficit/hyperactivity disorder (ADHD) typically report problems in neuropsychological functions and therefore undergo a thorough assessment. This thesis aimed to enhance the understanding of neuropsychological characteristics in adults with ADHD for improved differential diagnosis, optimized evaluation, and targeted treatments. First, we revealed that impairments in neuropsychological functions occur commonly in adults who were suspected of having ADHD but were not specific to adults diagnosed with ADHD. Neuropsychological assessments may be useful instruments to identify individuals’ cognitive strengths and weaknesses, rather than for the differential diagnosis of ADHD. Second, we observed that adults with ADHD reported significantly more severe ADHD symptoms in childhood than adults who did not meet the diagnostic criteria of ADHD. This finding highlights the importance of asking about childhood behavior retrospectively as it could potentially contribute to the differential diagnosis of ADHD. Third, we showed that the performances of different neuropsychological functions were not isolated but strongly connected in the ADHD group. We conclude that we may be able to shorten and streamline the clinical neuropsychological assessment to save valuable clinical resources. Finally, we demonstrated that attention performance may be stable over repeated assessments in the majority of patients with ADHD. This finding suggests that a one-time attention assessment is sensitive in revealing attention deficits and repeated assessment may not be necessary considering the limited clinical resources.