Attention deficit disorder (A.D.D.), also known as hyperkinetic syndrome of childhood, attention deficit disorder in children, minimal brain dysfunction (MBD), attention deficit hyperactivity disorder (ADHD), or mild brain dysfunction syndrome, is a common abnormal disease in children. These children have normal or basically normal intelligence, but have defects in learning, behavior and emotion, It is mainly manifested in inattention, short attention, too much activity, impulsive emotion, generally poor academic performance, difficult to get along with people at home and school, and often makes parents and teachers feel helpless in daily life.
The international report on the prevalence of ADHD in children is between 5% and 10%, with more boys than girls. The incidence of ADHD in preterm infants and cesarean section infants is higher, about more than 60%.
Since childhood, most children are easily excited, cry more, sleep less, feeding more difficult, it is not easy to form the habit of urinating and defecating regularly. With the growth of age, in addition to the increase of activities, they have uncoordinated movements, inattention or short concentration time, which are known as aimless, emotional impulse and lack of control ability, disobedience in class and learning difficulties. The children’s intelligence is normal, but their learning ability is generally low due to concentration, poor auditory discrimination ability and poor language expression ability. The clinical symptoms of school-age children are more prominent: more words, more small movements, excitement and quarrelling with others in class; The purpose of behavior is not clear, such as taking people and things, sometimes not avoiding danger; Not gregarious in collective activities; Stubborn, disobedient, rash and impolite in front of parents. Some children take an attitude of avoiding difficulties and become passive and retreat.
After age, many children have learning difficulties, although the intelligence level of ADHD children is mostly normal or close to normal. However, due to the above symptoms, it still brings some difficulties to learning. Some ADHD children have perceptual activity disorders. For example, when copying pictures, they often can’t distinguish the relationship between subject and background, can’t analyze the combination of graphics, and can’t integrate all parts of graphics into a whole. Some children read “6” as “9”, or “d” as “B”, and they can’t even tell the left from the right. The change of the former belongs to the obstacle of comprehensive analysis, and the latter belongs to the obstacle of spatial positioning. They also have difficulties in reading, Pinyin, writing or language expression. ADHD children answer without serious thinking, and their understanding is incomplete, which is also one of the reasons for learning difficulties. In addition, hyperactivity children often show some fixed soft symptoms of the nervous system, such as palm turning and finger opposite test.
Generally speaking, the fluctuation of clinical symptoms of hyperactive children is sometimes related to different occasions and activities of children. Hyperactive children have the most difficulty in maintaining their attention when they do homework, engage in repetitive activities or activities that require great effort, and do non novel things. The symptoms of ADHD can be alleviated in an absorbing, new situation or unfamiliar environment. Under the continuous and direct reinforcement, the maintenance of attention was significantly better than that of local and delayed reinforcement. Under the condition of guidance and frequent repetition, children with ADHD complete the task, and their attention maintenance problem is not big. In the absence of particularly strict norms and strict discipline requirements, hyperactive children are not different from normal children. The phenomenon that the symptoms fluctuate with the situation shows that the symptom severity of hyperactive children is affected by the environment and has a high degree of interaction with it.
ADHD in children may have different causes. It is generally believed that mild brain damage before, during or after delivery is an important factor, which is mainly related to brain injury and poisoning. Some people believe that urban environmental pollution and clinically asymptomatic mild lead poisoning can also be one of the causes. In recent years, through investigation and research, it is found that the incidence of some mental diseases such as alcoholism and morbid character in the lineage parents is higher than that in the control group, and the parents of children with ADHD have more history of childhood hyperactivity, The prevalence of siblings in ADHD children was three times higher than that in the control group, and affective psychosis was also common.
In addition, the father of ADHD children had antisocial personality characteristics or alcohol dependence, and the mother had hysteria. The adult relatives of hyperactive children with conduct disorder had higher rates of personality disorder, alcohol addiction and hysteria. The study on adopted children also found that the antisocial personality, alcohol dependence and hysteria of the biological parents of ADHD children were significantly higher than those of healthy parents or control children. The parents had a history of hyperactivity and conduct disorders in childhood and more people with mental disorders. The incidence rate of hyperactivity disorder in monozygotic twins is higher than that in twins. The incidence rate of sibling brothers is about 5 times that of half sib brothers. It suggests that the mild cerebral dysfunction of some children may have some effect on genetic factors, which may affect the psychological development of children. Many children failed to find the cause.
The data accumulated in recent years suggest that the disease has abnormal neurophysiological basis. It is considered that hyperactivity and inattention may be related to the insufficiency of catecholamine system (norepinephrine, formerly dopamine) in the brain. In animal experiments, hyperactivity occurs when drugs reduce or deplete the storage of dopamine in the brain of rats. Amphetamine is given to animals to increase the content of dopa in the synapse and the activity of dopamine neurons, which can make animals quiet. Clinically, amphetamine and promethazine (both strengthen the content of dopamine at synapses in the brain) are effective in the treatment of hyperactivity in children. In the probenecid test, the content of dopamine metabolites in children’s cerebrospinal fluid was also lower than that in the control group.