Childhood autism, also known as childhood autism, is a group of psychiatric disorders characterized by severe isolation, lack of emotional response, impaired language development, stereotyped repetitive movements, and peculiar reactions to the environment. Originally called infantile autism, it is now collectively referred to as autistic disorder. It is a pervasive developmental disorder. It is a severe developmental disorder of infants and young children, which differs greatly from autism in adults in terms of cause, developmental approach and treatment. It is characterized by abnormalities in social interaction; communication; and restricted, stereotyped, and repetitive behaviors, as well as an onset before the age of three. In addition, non-specific problems such as phobias, sleep and eating disorders, anger and self-injury are often seen. The main symptom of autism is a failure to interact with others and to establish normal social relationships. The child is immersed in his or her own world and is unable to communicate and interact with others or even his or her own parents using words, expressions and movements. People with autism can have difficulty learning the language of normal people, interacting with others and communicating with the outside world, and they may repeat several actions (clapping their hands, shaking). When changes occur in daily life, they will strongly resist. The effects of autism on behavior, in addition to language and social difficulties, can include extreme exuberance or frustration in front of parents and family members. Lonely and dissociated, they will not establish normal connections with people i.e. they lack the tendency to interact and communicate with people, they do not actively seek out children to play, they behave evasively when others approach them to play, they do not respond to calls, and they always prefer to move around and play by themselves alone. Some children do not refuse others, but they do not interact with children, i.e., they lack social interaction skills. For example, when looking for children, they either suddenly pat people or grab them or suddenly go over and hug them, and then they go away, as if patting or grabbing people is not for contacting people but just an action, or there is only a form of contact without the content and purpose of contacting people. Their loneliness is also manifested in the fact that they do not care about what is going on around them, they seem to listen without hearing, ignore, and do what they want to do, without care, as if no one else is around, and what is going on around them seems to have nothing to do with him, it is difficult to attract his interest and attention, their eyes often change, and they do not easily stay on the things that others ask them to pay attention to, they seem to live in their own little world. In addition, their eyes do not look at each other or even avoid each other’s gaze, and their gaze wanders during normal activities, often squinting, squinting or afterglowing when looking at people, rarely looking straight ahead and rarely showing a smile, and never greeting people. Most of the children have very little speech, and in severe cases, they are almost lifelong non-verbal, with limited vocabulary. Some children can speak, but their voices are small, low, or they repeat monotonous words to themselves. Some children will only imitate what others have said and will not use their own language to converse. Many children do not ask or answer questions, but simply repeat what others have asked them. Confusing pronouns, such as “you” and “he”, are often used instead of themselves. Many children with autism also have frequent screaming, which sometimes persists until the age of 5 to 6 years or more. Children with autism often focus on one or more games or activities for a long period of time, such as being obsessed with spinning pot lids, monotonously placing blocks, watching TV commercials and weather forecasts, and having no interest in cartoons, children’s TV, or movies that children usually enjoy. Some children have to eat the same food every day, walk the same route when they go out, and require the same commode for defecation, and if there is any change, they cry and show obvious anxiety reactions, refusing to change their original habits and behaviors and having difficulty adapting to the new environment. Most children also show purposeless activities, excessive activities, monotonous and repetitive jumping, clapping, waving, running and rotating, and some even show self-injury and self-harm, such as repeatedly picking their nostrils, picking their mouths, biting their lips, sucking and other actions. Most of them are mentally stunted and unbalanced. Most of them are mentally retarded compared with their peers, while a few of them have normal or near normal intelligence. However, some of them are surprisingly good in one aspect of intellectual activity, which is unbelievable. Many of them have strong mechanical memory ability, especially for writing and symbols. For example, a 3 or 4-year-old child is particularly fond of recognizing words and asks what to read when he sees them, and remembers them after only one question. According to statistics, 20% of children with autism have normal intelligence and about 10% have abnormal intelligence. Most children with autism have a good memory, especially in mechanical memory. Some children may also have perceptual impairment and may be dull or hypersensitive to various senses such as sight, hearing and touch. Some have cognitive impairment, low intelligence and poor abstract thinking skills, and a few children may have seizures. Children with autism are sometimes deaf and do not respond to sounds. While normal children are startled by sounds such as a barking dog, autistic children are indifferent. They are also less sensitive to pain, heat and cold, and do not like to make friends, preferring to be alone and rarely touching the eyes or laughing of others. The causes of autism have been studied extensively in terms of genetic, organic and environmental factors, however, so far, it has not been possible to clarify the etiology and pathogenesis of autism in children but at least it is seen as an abnormal behavioral syndrome caused by a wide range of biological causes of pervasive developmental disorders. 1. Genetic factors: The homozygosity rate of the affected siblings is higher than that of others, and the homozygosity rate is higher in monozygotic twins. Their fathers and older siblings were also found to have long y chromosomes, thus suggesting that they are related to genetic factors. 2, organic factors: such as brain injury, maternal rubella infection during pregnancy, after birth suffered from meningitis, encephalitis, etc.. In recent years, studies have found that enlargement of the left temporal horn of the ventricle is more common in children with this disorder, suggesting lesions of the medial temporal lobe structures, which may be due to metaplasia of brain tissue. Recent studies have demonstrated that in children with juvenile autism, the immune system may mistake an essential brain protein for a foreign body and be engulfed. This results in brain damage, which may be characteristic of what causes the disorder. The presence of emotional, intellectual and communicative deficits is also associated with brain lesions. 3, environmental factors: In the past, some people believe that the early life environment of cold and overly rationalized nurturing methods, the lack of rich and appropriate stimulation, not taught to social behavior, is an important factor in the development. Children who have been in a monotonous environment for a long time will use repetitive actions for self-stimulation and will not be interested in the external environment. Most of the parents of children with this disorder are professional technicians, highly educated and relatively intelligent, but stereotypical in their actions and have a tendency to be obsessive, cold and stubborn towards their children and lack of warmth in the family. Nowadays, this view is denied. It has been confirmed by research that it is due to some kind of brain lesion, the cause of which, whether it is a virus, or a metabolic disorder, is still inconclusive. How to determine if a child has autism For children with autism, only early detection, early intervention, and behavioral correction can help them close the gap with normal society and allow them to integrate into society as soon as possible. How can we detect autistic tendencies in children at an early stage? The following 18 behaviors are early manifestations of autism: 1. unresponsiveness to sounds; 2. difficulty intervening with peers; 3. refusal to accept change; 4. indifference to the environment; 5. parroting; 6. preference for spinning objects; 7. inexplicable laughter; 8. resistance to normal learning methods; 9. strange ways of playing; 10. unbalanced motor development; 11. insensitivity to pain; 12. lack of eye-to-eye; 13. special dependence on an object; 14. unexplained crying; 15. special mobility or immobility; 16. refusal to hug; 17. lack of fear of real danger; 18. use of movement to express needs.