Here is a scenario playing out in clinics across the country: an older adult walks in reporting trouble with memory and mental processing. Their physician, reasonably, considers early dementia. The tests begin. The wait is agonizing. But what if the root cause is something else entirely — a condition written off as a childhood problem decades ago?
A new study published in the Journal of Attention Disorders adds important evidence to a growing concern in geriatric medicine: undiagnosed or unmanaged ADHD in older adults may be masquerading as early cognitive decline, and the two are remarkably difficult to distinguish from symptom descriptions alone.
Marrium Mansoor at Virginia Tech led the research, which drew on data from approximately 1,300 American adults over 50 participating in the Health and Retirement Study — a large, nationally representative dataset that gives the findings real statistical weight. Participants were divided into three age bands: 55-64, 65-74, and 75-84. Each completed the Adult ADHD Self-Report Scale alongside a battery of cognitive tests covering working memory (Serial 7s), episodic recall, and fluid intelligence.
The central finding is striking in its consistency: inattention symptoms were reliably associated with lower performance across all three cognitive domains — and this association held across every age group tested. An 84-year-old with high inattention scores showed the same pattern of cognitive underperformance as a 55-year-old with the same profile. Critically, the effect was specific to inattention — hyperactivity and impulsivity showed far less consistent relationships with cognitive outcomes. Depression, a common confound in both ADHD and dementia research, was ruled out as the primary driver.
This matters clinically for a straightforward reason. The cognitive fingerprint of inattentive ADHD — poor working memory, slower processing speed, weaker episodic recall — overlaps substantially with the early signs of neurodegenerative disease. A clinician who does not think to screen for ADHD in a 70-year-old may never consider the possibility, especially given how thoroughly the condition has been framed as paediatric medicine.
The implications for misdiagnosis are real. Interventions developed for ADHD — mnemonic strategies, structured routines, targeted pharmacology — are distinct from dementia care pathways. Getting the diagnosis right determines the treatment direction. For older adults currently sitting in waiting rooms wondering why their memory keeps failing them, that distinction could be genuinely consequential.
Now for the honest accounting of what this study does and does not show: it demonstrates association, not causation. The design is cross-sectional, meaning researchers measured symptoms and cognition at one point in time rather than tracking patients across years. It relied on self-reported ADHD symptoms rather than clinical diagnoses — a meaningful methodological caveat. And because the study excluded participants with existing dementia diagnoses, survival bias may affect the results in the oldest cohort.
None of these are fatal limitations. They are the normal constraints of population-health research at this scale. What they tell us is to treat the finding as a clear signal worth following — with longitudinal studies, clinical screening trials, and greater awareness among practitioners that ADHD is not just a childhood condition. The brain doesn't forget how to be inattentive just because it has aged.
