Children with ADHD have difficulty paying attention and are hyperactive and impulsive, according to the "Diagnostic and Statistical Manual of Mental Disorders" (DSM-IV-TR). These symptoms are considered diagnosable when they are maladaptive and inconsistent with the developmental level for the child's age and have persisted for at least six months. For ADHD to be diagnosed, the symptoms must be present before age 7 and occur in two or more settings.
Brain Functioning
According to P. A. Teeter in "Interventions for ADHD: Treatment in Developmental Context," the brain's frontal lobe, basal ganglia, caudate nucleus and cerebellum play a significant role in ADHD because they are involved in processes that regulate behavior. These processes include self-monitoring, motor control, memory and inhibition.
Heredity
According to the DSM-IV-TR, heredity is the most common cause of ADHD. It is more common in first-degree biological relatives of children with ADHD than in the general population. Genetic factors influence the levels of hyperactivity, impulsivity and inattention. Several twin studies have found that ADHD is highly heritable. According to myadhd.com, research has found an 82 percent concordance rate for ADHD in identical twins compared to a 38 percent concordance rate for ADHD in non-identical twins. ADHD has been shown to have an exceptionally high heritability rate compared to other behavioral disorders.
Exposure to Toxins
Researchers have found a correlation between mothers who smoked tobacco and/or drank alcohol during their pregnancy and the development of behavior and learning problems in their children, reports myadhd.com. A similar association between lead exposure and hyperactivity has been found.
Injury to the Brain
Injury to the brain as the result of trauma, brain tumor, stroke or disease can cause problems with inattention and poor regulation of motor activity and impulses.
References
- myADHD: Causes of ADHD
- American Psychiatric Association; "Diagnostic and Statistical Manual of Mental Disorders"; 2000
- "Interventions for ADHD: Treatment in Developmental Context"; P. A. Teeter; 1998
