Mental retardation is a violation of the normal rate of mental development, when certain mental functions (conitive, emotional-volitional) lag behind in their development the standard psychological development of a child for the corresponding age. ZPR as a psychological and pedagogical category is used only in preschool and primary school age; if by the end of this period there are signs of underdevelopment of mental functions, then they talk about constitutional infantilism or use other terms appropriate to the situation. Delayed psychological development manifests itself in a violation of the timely development of individual functions, for example, memory or attention functions. It is worth noting that mental retardation is not mental retardation. This is a reversible process. There are many reasons for delayed mental development in children:✔️ Development of diseases in the mother during pregnancy (for example, acute respiratory diseases);✔️ Chronic diseases in the mother;✔️ Use of alcohol or drugs during pregnancy;✔️ Nicotine addiction , preserved during pregnancy;✔️ Use of unwanted medications during pregnancy;✔️ Physical damage received by the child during childbirth;✔️ Anesthesia in infancy;✔️ Trauma suffered during the first 12 months after birth;✔️ Lack of contact with the child, his neglect. 📈Currently, there are more and more children with delayed psychological development. And there are more boys in quantitative terms than girls. This is due to the fact that girls’ brains are designed in such a way that if the left hemisphere is deformed, the right hemisphere can take over all the functionality, and vice versa. In addition, we should not forget that the manifestation of this diagnosis may vary depending on time range and stages of manifestation. However, there are a number of features that are characteristic of most children with this diagnosis.