The root causes of obsessions in children with both schizoform disorders and neurotic spectrum disorders vary quite widely, and was not always possible to identify. However, it is worth noting that in children with neurotic disorders, obsessions more often arose as a result of the pathological influence of personally significant factors, while in children with schizoform spectrum disorders, factors unrelated to the life situation, personality and relationship system were usually the triggers for the manifestation of obsessional symptoms the patient. In children with emotional and behavioral disorders, the root cause of obsessions was always psychotraumatization. The structure of obsessions in children with schizoform spectrum disorders should be called “kaleidoscopic” — changeable and undependent on external circumstances. In children with neurotic disorders, a “raster” structure of obsessions prevailed — one that smoothly changed from the initial subject of obsessions. In children with emotional and behavioral disorders the “monotonous” theme of obsessions prevailed — unchanged throughout the entire period of the disease, reflecting the initial psychotraumatization. Compulsions that accompanied the appearance of obsessions in patients from G1 usually required urgent implementation, and could not be postponed even in view of the presence of external observers. Patients with disorders of the neurotic spectrum had significantly more control over compulsions and in most cases could reduce them or postpone them until a more appropriate moment. In children with emotional and behavioral disorders compulsions due to their clinical essence (obsessive memories) were often imperceptible to others. Key words: obsessions, compulsions, psychopathology, neurotic disorders, child psychiatry.