The causes of ADHD in children include:
There is strong evidence from family and twin studies that ADHD has a significant genetic component. Molecular genetic research has indicated that the genetic structure of ADHD is complex, and comprehensive results from whole-genome scans have not yet been obtained. Several genes have been associated with ADHD, including DRD4, DRD5, DAT, DBH, 5-HTT, HTR1B, and SNAP-25. Research has found that the heritability of ADHD can reach 70-80%. If a sibling has ADHD, the likelihood of the individual having it may be 3-4 times that of the general population.
Some studies suggest that environmental factors may be more influential in children and adolescent psychopathology than genetic factors. Brain injuries, exposure to environmental factors during pregnancy or early life (such as lead exposure), maternal alcohol and tobacco use during pregnancy, premature birth, low birth weight, and other factors have been linked to the development of the disorder. Excessive sugar consumption, excessive television watching, and factors related to parenting style, family relationships, and social and environmental influences can worsen the symptoms of ADHD.
ADHD symptoms in hyperactive children include the following:
Children with attention deficit hyperactivity disorder (ADHD) continue to grow up in a state where they cannot concentrate. If the symptoms persist over a long period, they may become more severe and cause difficulties in school, at home, or when interacting with friends. Generally, children with ADHD may exhibit the following symptoms: daydreaming frequently, forgetting or losing things, being restless, talking excessively, being prone to careless mistakes or unnecessary risks, finding it difficult to resist temptations, and struggling with social interactions. Since the symptoms can change over time, their presentation may also vary.