information:filtering
Research and contributions

By 1959, she prepared yet another doctor-of-sciences dissertation titled "Thinking disorders in the mentally ill." In her dissertation work, Zeigarnik described the results of a study of 710 patients who were diagnosed with schizophrenia, epilepsy, cerebrovascular disease, brain injury, intellectual disability, encephalitis, progressive paralysis, manic depressive psychosis, and personality disorders. In fact, she participated in the studies of other patients and other themes as well during the same period: the issues of self-regulation, mediation of behavior (the term mediation was introduced by Lev Vygotsky), organization of treatment for patients with nervous and mental diseases, etc. Zeigarnik considered three main categories of thinking disorders: distortion of the generalization process, distortion of the logical structure of thinking, and distortion of goal-oriented thinking. She explored which subcategories of these three main categories are characteristic of certain diseases and how best to identify them. It turned out that there are no thinking disorders that would be characteristic of only one diagnosed disease. Yet, for each disease, some are more typical and others are less. Comparison of experimental psychological and clinical data made it possible to diagnose diseases more effectively. Experimental data led Zeigarnik to conclude that the usual division of mental activity into separate processes is artificial and does not allow a consistent description of the disintegration of thinking. Thinking disintegrates not as a separate process but as an activity. Largely due to the research of Zeigarnik, in the 1940–1950s in the Soviet Union, there was an accumulation of a large array of systematically built research data, which later formed the basis of experimental abnormal psychology and hugely expanded during the next decades.