Longitudinal Cognitive Performance of Older Adults With ADHD Presenting to a Cognitive Neurology Clinic: A Case Series of Change Up to 21 Years

Abstract

Background: The neuropsychological features of older adults with ADHD are largely unknown. This retrospective chart review aims to elucidate their cognitive trajectories using a case series of six older adults with ADHD presenting with memory complaints to a cognitive neurology clinic, whom we argue are a particularly relevant group to study due to their potential to mimic neurodegenerative syndromes.Methods: Participants were included if they were age 40 or older at intake, had ADHD based on DSM-5 criteria, and had cognitive data collected prior to 2014 with follow-up at least 5 years later.Results: Five men and one woman were included (M = 53.8 years at intake) and had an average of 135.0 months of follow-up data available. Despite notable between- and within-subject variability, cognition generally improved or remained stable across visits. Two participants experienced notable memory decline, but a global consideration of their performance in other domains suggests these deficits may be frontally-mediated.Conclusion: In this small sample, cognition remained generally unchanged across 5–21 years. Isolated impairments likely reflect substantial intra-individual variability across time and measures.

From attention-deficit hyperactivity disorder to sporadic Alzheimer’s disease—Wnt/mTOR pathways hypothesis

“…A recent study ( Kakuszi et al, 2020 ), provided findings consistent with the “last in, first out” hypothesis, which refers to a mirroring pattern of brain development and aging, i.e., relatively late-developing brain regions with age become the early degenerating ones, indicating that, in addition to delayed neurodevelopment, ADHD may also be associated with a premature age-related deterioration. On the other hand, in a very small longitudinal study of 6 ADHD adults with an average of 135 months of follow-up data, no memory decline was observed, however, this might be due to the small sample size and the effect of medication (3/6 participants were taking MPH and 5/6 were taking unspecified antidepressants) not taken into account ( Callahan et al, 2021 ). The same group conducted cognitive and neuroimaging assessments of adults (age 50–85 years) with ADHD ( n = 40), MCI = ( n = 29), and controls ( N = 37) ( Callahan et al, 2022 ).…”