Excerpt
With a prevalence rate of about 5% of children worldwide, attention-deficit/hyperactivity disorder (ADHD) is one of the most frequent neurodevelopmental childhood disorders (Polanczyk et al.
2007). For a long time, ADHD had been understood as an exclusive childhood disorder, which grows out by adolescence and is nonexistent in adulthood (Klein and Mannuzza
1991; Ross and Ross
1976). However, a large body of research in the last two decades demonstrated that ADHD persists up into adulthood as a valid and reliable disorder (Barkley et al.
2002; Biederman
2005; Faraone et al.
2000; Mannuzza et al.
1998; Rasmussen and Gillberg
2000). The extent to which symptoms of ADHD persist from childhood to adulthood is difficult to estimate due to a high heterogeneity of methodologies and designs between studies. Therefore, estimations of persistence rates in children with ADHD who still suffer from symptoms of ADHD in adulthood vary between 30 and 60% (Biederman
1998; Biederman et al.
2000; Seidman et al.
2005; Willoughby
2003). A more recent epidemiologic study performed by Barbaresi et al. (
2013) reported a persistence of ADHD into adulthood in 29–38% of cases. Although there is disagreement about the actual percentage of ADHD children who will still suffer from the disorder in adulthood (Willoughby
2003), there is little doubt that it is a substantial proportion. As ADHD symptoms have also been reported in older adults, lifetime stability of ADHD is assumed (Guldberg-Kjär et al. 2013; Kooij et al.
2005; Michielsen et al.
2012; Semeijn et al.
2016). Regarding the developmental trajectory, it is notable that the clinical picture of ADHD in adulthood differs from the clinical picture of childhood ADHD. Motor symptoms of hyperactivity/impulsivity were shown to be less dominant in adults with ADHD, whereas cognitive dysfunctions (such as inattention and disorganization) were found to become more pronounced in adult ADHD (Biederman et al.
2000; Davidson
2008). Moreover, symptoms of ADHD in adulthood were demonstrated to be closely linked to academic failure, social dysfunction, low self-esteem and reduced quality of life (Agarwal et al.
2012; Biederman
2005; Canu and Carlson
2007; Canu et al.
2008). …
