Attention deficit hyperactivity disorder (ADHD) is the most common psychiatric diagnosis in childhood and adolescence, and its prevalence is similar in those countries where epidemiological studies have been conducted. The mean prevalence worldwide was recently estimated at 5.48% of school-aged children – meaning that, in France, it is likely that 600,000–800,000 children are affected by ADHD. Since ADHD has a strong genetic origin, it persists into adulthood in the majority of cases: the mean prevalence was estimated at 3.5%, which means that about 1.5 million adults are likely to be affected in France.