Attention Deficit/Hyperactivity Disorder (ADHD)
The concept of treating aberrant childhood behavior as a medical disorder dates as far back as the 1700s and has always been fraught with controversy regarding what constitutes a “disease” as opposed to typical, albeit difficult, childhood behavior (Taylor 2011). The diagnosis and treatment of ADHD, especially among children, continues to remain a hotly debated topic today as many aspects of the condition are subjective and different systems to classify the disease are often used by physicians from different countries (Parens 2009).
Technological advances in neuroimaging techniques have allowed scientists to observe the brains of children diagnosed with ADHD and compare them to those of adolescents without the condition. Several studies have identified subtle differences in brain structure or function among ADHD children. For example, a study employing functional magnetic resonance imaging (fMRI) showed that the brain networks in children with ADHD activate in different patterns compared to healthy children’s brains (Massat 2012). Other studies suggest that brains of ADHD children display variations in the volume or density of various brain regions compared with non-ADHD kids (De La Fuente 2013; Pastura 2011; Tomasi 2012).
Evidence suggests that several aspects of the variation in brain function observed in ADHD are attenuated by psychostimulant drugs such as methylphenidate. This has led some researchers to speculate that reversion of brain network structure and activity to normal may underlie the therapeutic benefits of psychostimulant drugs (Spencer 2013; Kasparek 2013).