Attention-deficit/hyperactivity disorder as a metabolic encephalopathy

Abstract

Attention-deficit/hyperactivity disorder (ADHD) is the most commonly diagnosed psychiatric disorder of childhood (American Academy of Pediatrics, 2000; Smalley, 1997). It affects 5-10% of children worldwide and persists through adolescence into adulthood in about half of the affected individuals (Faraone et al., 2003; Meyer et al., 2004; Adewuya and Famuyiwa, 2006). Children with ADHD are characterized by severe, developmentally inappropriate, motor hyperactivity, impulsivity and inattention that results in impairment (failure at school) due to an inability to sit still, difficulty in organizing tasks, not remembering instructions, being easily distracted, fidgeting, difficulty with tasks that require sustained attention and risk-taking (American Psychiatric Association, 1994; Sagvolden et al., 2005a; Thapar et al., 2007; Abikoff, et al., 2002). There is increasing recognition that ADHD is associated with later drug and alcohol misuse and problems both socially and in the work environment (Thapar et al., 2007). In some cases the disorder is associated with antisocial behaviour and criminality (Thapar et al., 2007). Three subtypes of ADHD have been recognized, the predominantly inattentive subtype, predominantly hyperactive-impulsive subtype and the combined subtype (American Psychiatric Association, 1994).