Aim. Results of research on the learning of ideas by children with specific mental disturbances are presented in the article below. In the introduction, there are some psychological concepts related to the learning of ideas, and psychopathological concepts concerning the subject of research. Method. In the further part of the article, Andrzej Lewicki's views are presented. His concept of abstraction (i.e. positive and negative abstraction) constitutes a development of classical views deriving from the Wurzburg school. Results. In the article, there arc the results of a clinical experiment with regard to the learning of ideas, with the participation of 43 young, hospitalised patients in one of the Neuropsychiatric Hospitals for Children and Youths in the Mazowieckie Province, with the following diagnoses: behavioural disturbances, neurotic disturbances, psychotic disturbances, organic disorders. The young patients were aged from 8 to 16 years. It turned out that as far as quantity was concerned, the best quantitative results were achieved by young patients with diagnosed neurotic disturbances, and the worst results were characteristic for patients with psychotic disturbances. Conclusions. The results turned out that the four groups compared had tendencies to make qualitatively different errors while learning new ideas during the clinical experiment.