The Potential Role of Neuroendocrine in Patients with Attention-Deficit/Hyperactivity Disorder

Abstract

Attention-Deficit/HyperactivityDisorder (ADHD) is one of the most prevalent neurodeve‐ lopmental disorders among children. It affects 3-10% of school-age children (Polanczyk et al., 2007), and a prevalence rate of 7.5% was reported in a local Taiwan study (Gau et al., 2005). The core symptoms of ADHD are inattention, hyperactivity, and impulsivity, and ADHD patients are commonly comorbid with other neuropsychiatric disorders, such as Op‐ positional Defiant Disorder (ODD), Conduct Disorder (CD), and tic disorders (American Psychiatric Association, 2000; Spencer et al., 2007). The most well-known neurobiological hypotheses to account for the complexity in etiology of ADHD are the dysregulation of cate‐ cholaminergic neurotransmission (Biederman & Faraone, 2002). In recent years, many re‐ searchers have raised concerns with regards to the potential roles of the neuroendocrine system in the pathogenesis of ADHD (Dubrovsky, 2005; Golubchik et al., 2007; Goodyer et al., 2001; Martel et al., 2009; Strous et al., 2006), based on observations of the epidemiological data of ADHD. ADHD is more prevalent in boys than in girls, with the ratio ranging from 4 to 1 to as much as 9 to 1, and boys generally exhibit more impaired cognitive control than girls (American Psychiatric Association, 2000). In addition, longitudinal studies have shown that there is a clear decline of symptoms with age, and a possible remission occurs after the age of 12 (Polanczyk & Rohde, 2007). The neuroendocrine system, the activation of which is closely associated with age and gender, may influence developing neural circuitry and be‐ havioral systems; thus it has reasonably been speculated that this system plays a role in the pathogenesis of ADHD (Martel et al., 2009).