The decreasing prevalence of ADHD across the adult lifespan confirmed

Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder common in both children and adults. Diagnostic criteria are based on two core symptom domains: inattention and hyperactivity-impulsivity. Additionally, symptoms should first occur before age twelve and be accompanied 
by impairments in daily life [1]. In childhood, ADHD has an estimated prevalence of 5%-7% [2,3]. It is well 
known that, during adolescence, inattention symptoms, and in particular hyperactivity-impulsivity symptoms, 
become milder for a subset of children diagnosed with ADHD. Accordingly, prevalence estimates in adulthood 
are lower, at 3%-5% [2,4]. It is important to note, however, that compared to childhood ADHD, adult ADHD 
has received far less research attention, with adult ADHD definitions strongly varying between studies and few 
large population-based data sets spanning the full adult lifespan available [4-7]. Consequently, it is unclear 
whether the prevalence of adult ADHD changes with age. That very few older individuals with ADHD are diagnosed and treated highlights the importance of this issue. A recent meta-analysis focusing on individuals with 
ADHD aged fifty years and older identified a prevalence of 0.23% diagnosed with ADHD and 0.09% treated 
for ADHD [6]. All things considered, this raises the question whether the prevalence of ADHD is indeed very 
low beyond age fifty, indicating a decline across adulthood, or whether we underrecognize ADHD in old age