These studies present first evidence of a link between ADHD and risk of dementia, specific to LBD. Strengths include well-powered analyses and extensive follow-up periods (>10 years) in most studies. However, six (Curtin et al., 2018; Fluegge and Fluegge, 2018; Tzeng et al., 2019; Fan et al., 2020; Du Rietz et al., 2021; Zhang et al., 2021) rely on ICD diagnostic codes extracted from electronic health records, and there are limitations around the validity and accuracy of these codes, particularly for a disorder that is notoriously difficult to detect in adults (Newcorn et al., 2007; Ginsberg et al., 2014). The remaining two (Walitza et al., 2007; Golimstok et al., 2011) are limited by potentially biased and inaccurate self-reported retrospective childhood ADHD symptoms in small samples of cognitively impaired participants.

https://www.frontiersin.org/articles/10.3389/fnagi.2021.826213/full