Attention deficit hyperactivity disorder (ADHD) is a condition children are highly susceptible to. However, young children often struggle to articulate their symptoms, making parental observation crucial. In recent years, we've observed a significant rise in childhood ADHD cases, causing considerable concern for many parents. What causes ADHD in children, and what are its typical symptoms?
I. Causes of ADHD
1. Genetic Factors
Current research indicates this disorder is linked to genetic factors, with a heritability coefficient of 0.75–0.91. The exact mode of inheritance remains unclear but may involve polygenic inheritance. Molecular genetic studies suggest associations with polymorphisms in dopamine receptor genes.
2. Neurophysiological Factors
Children with ADHD exhibit a high rate of abnormal electroencephalograms (EEGs), primarily characterized by increased slow-wave activity. Power spectrum analysis of EEGs reveals heightened slow-wave power, reduced alpha wave power, and decreased average frequency. This suggests delayed maturation of the central nervous system or insufficient cortical arousal in affected children.
3. Mild Brain Injury
Mild brain injuries occurring during pregnancy, the perinatal period, or after birth due to various causes may contribute to the disorder in some children. However, no single brain injury is present in all affected children, nor do all children with such injuries develop the disorder. Furthermore, many children show no evidence of brain injury.
4. Neuroanatomical Factors
MRI studies report reduced corpus callosum and caudate nucleus volume in affected children. Functional MRI studies also indicate decreased metabolism in the caudate nucleus, frontal regions, and anterior cingulate cortex.
5. Psychosocial Factors
Adverse social and family environments—such as extreme poverty, parental conflict, or inappropriate parenting styles—can increase a child's risk of developing this disorder.
6. Other Factors
This disorder may be associated with zinc or iron deficiency and elevated blood lead levels. Cola, coffee, and food additives may increase a child's risk of developing this disorder.
II. Symptoms of Pediatric ADHD
1. Attention Deficit
Manifested as age-inappropriate difficulty sustaining attention and short attention span, this is the core symptom. Patients often struggle to maintain focus during lectures, homework, or other activities, easily distracted by external stimuli. They fail to attend to details in tasks or activities, frequently making careless mistakes.They struggle to sustain attention and often deliberately avoid or resist tasks requiring sustained concentration, such as classroom or homework assignments.
2. Hyperactivity Patients frequently appear restless, engage in excessive fidgeting, and cannot sit still, often squirming in their seats. They may leave their seats without permission in classrooms or other quiet settings, running around or climbing. They struggle to engage in quiet activities or games, remaining constantly busy throughout the day.
3. Impulsive Behavior
Acting quickly without sufficient information. Behaving impulsively, acting on momentary interests without considering consequences, often leading to fights or disputes with peers and negative outcomes. Interrupting others while they speak, rushing to answer before teachers finish questions, and being unable to wait patiently in lines.
4. Learning Difficulties
Attention deficits and hyperactivity interfere with classroom comprehension, homework completion speed and quality, leading to poor academic performance that often falls below what their intelligence level would suggest.
Experts advise parents to closely observe their child's behavior. If you notice unusual signs—such as excessive activity, persistent restlessness, significant learning difficulties, or a lack of motivation despite intelligence—take it seriously. Seek a thorough medical evaluation when necessary to prevent or mitigate the condition.