Earlier considered a disorder affecting only children, today worldwide adult ADHD prevalence is estimated at 2.5%. The core symptoms; inattention, hyperactivity and impulsivity, often persevere impacting many fields of life.

To estimate the prevalence of ADHD symptoms in the general Finnish adult population.

We started with a population based and randomly drawn sample of 3000 adults, aged 18–44 years. When contacted, participants were provided three alternative ways to participate (online, letter, telephone interview). Using the adult ADHD rating scale (ASRS) screener all participants (n = 748) were categorized into groups: possibly symptomatic (≥4 points), controls (≤2 points) and undefined (3 points). Fifty-seven possibly symptomatic consented to further evaluation by a telephone interview, together with two age- and gender matched controls each.

Using the results from the ASRS screener, we calculated a 10.96% prevalence. Analysis of the complete ASRS resulted in a 5.08% and the recommended two-step evaluation in a 3.34% prevalence, out of whom two thirds considered being moderately or severely impaired by the symptoms.

This study suggests that a large number of adults in the general population are negatively affected by ADHD symptoms, almost all unrecognized by health care professionals. As ADHD is a burden for the patient, his family and the society, adult ADHD deserves greater attention in the future.

The authors have not supplied their declaration of competing interest.