Treatment of Attention Deficit Hyperactivity Disorder Comorbid with Epilepsy

Abstract

Pharmacologic treatment approaches for either ADHD (attention deficit hyperactivity disorder) or epilepsy, individually, are well studied. However, very few studies have addressed treatment strategies for children with both conditions. This is unfortunate, as ADHD is the most common psychiatric comorbidity occurring in children with epilepsy (Salpekar & Dunn, 2007). Although the prevalence of ADHD in the general pediatric population ranges from 5–10%, the prevalence of ADHD in children with pediatric epilepsy ranges from 20–38%. The predominantly inattentive subtype is more common (24%) than the combined type (11%) or predominantly hyperactive-impulsive subtype (2%) (Dunn et al., 2003). In some cases, significant distractibility may be identified even before the diagnosis of epilepsy is made (Hesdorffer et al., 2004). Epilepsy is a common illness, affecting nearly 1% of the general pediatric population, and is defined by having two or more unprovoked, afebrile seizures (Davis et al., 2010). The most widely used classification system, developed by the International League Against Epilepsy (ILAE), differentiates epilepsy by etiology and seizure type (Engel, 2006). Specific seizure types are distinguished as either partial or generalized. Partial seizures are identified when the initial clinical or electroencephalographic (EEG) change reflects a focal area of the brain, while generalized seizures are identified where the initial EEG change is widespread throughout the brain. Partial seizures are further classified as simple, if there is no change in consciousness, or complex, if consciousness is altered. Complex partial seizures are frequently associated with auras, five to ten second periods prior to a seizure event, during which an individual may experience physical sensations such as epigastric discomfort, or emotional symptoms such as fear or panic. Seizure episodes or auras may interrupt consciousness, and the result may be apparent distractibility or altered attention. Absence seizures, typically characterized by episodes of 10 seconds or more of staring and altered consciousness, are commonly misdiagnosed as inattention and represent an important differential diagnosis for ADHD (Williams et al., 2002).