It is known that the earlier the problem of a child's mental development is identified, the easier it is to eliminate (minimize) it. Sources of information about the possible presence of such a problem can be: behavior, self-care skills, motor skills, the appearance of the child, facial expressions, neatness, speech and vocabulary, meaningful execution of instructions and manners of communication. At each age, children have certain manifestations (markers) of possible mental illness, which parents should pay attention to.