Externalizing Disorders in the Pediatric Patient

Attention-deficit hyperactivity disorder, or ADHD, is classified as a neurodevelopmental disorder that develops before 12 years of age, and is characterized by developmentally inappropriate behaviors, including inattention, impulsiveness, and hyperactivity.

The symptoms of ADHD are believed to be caused by decreased levels of certain neurotransmitters, specifically dopamine, which is involved in behaviors like risk taking, impulsiveness, and reward; norepinephrine, which is involved in alertness, attention, and focus; and serotonin, which plays a key role in regulating mood. There are also some structural abnormalities in parts of the brain, like the frontal lobe, cerebellum, and basal ganglia that are present in the brains of children with ADHD.

Okay, so the exact causes of ADHD aren't well understood, but it is likely due to a combination of genetic and environmental factors. ADHD has a strong genetic component, so a child with a parent or sibling diagnosed with ADHD is more likely to develop it themselves. ADHD is also associated with prenatal exposure to tobacco smoke, alcohol, or illicit drugs, as well as perinatal problems like prematurity or low birthweight. Other risk factors include exposure to lead; certain infections, like encephalitis; and adverse childhood experiences, such as neglect, abuse, or exposure to domestic violence.

Now, children are often fidgety, talkative, and inattentive, but the behaviors of a child with ADHD are different because they’re considered developmentally inappropriate; they’re persistent, or always present; and they interfere with the child’s functioning and development.

One of the major symptoms of ADHD is inattention, meaning the child may find it difficult to focus on tasks like conversations, games, or reading, and they're easily distracted by extraneous stimuli like people talking, music, or other background noises. They often don’t appear to be listening when spoken to; they have difficulty following instructions; and they tend to be forgetful. As a result, they often make mistakes; lose things, like books or papers; and struggle to finish tasks, like chores and homework assignments.

The other major symptoms of ADHD are hyperactivity and impulsivity, which can manifest as excessive fidgeting, like tapping their hands or feet or squirming in their seat. Also, the child often seems restless and may spontaneously get up in situations where remaining seated is expected, like in a classroom. Likewise, they may have a hard time waiting their turn for a game or task, and they can be very talkative and may interrupt when another person is speaking or blurt out answers before a question has been fully asked.