Aim. The characteristics of thinking processes in patients with serious illness and evaluation of the adaptation level with the content of thinking processes consideration. Material and methods. The study included 56 patients rehabilitating after serious neurologic diseases (haemorrhagic and ischemic stroce) and 18 patients during oncological treatment (leukemia) together 74 persons. In the research a diagnostic survey was applied, using the standardized questionnaire: Adaptation of Illness Scale (AIS), Posttraumatic Growth Inventory PTGI (PTGI) and the author’s questionnaire Rumination Scale (RS). Results. During the time elapsed since the fall sick the content of patients’ sic thoughts has changed statistically significantly, especially about: the meaning of live, recognizing the benefit in the treatment and blocking negative thoughts and problems pondering. Tree figures of the patients adaptations to illness have been identified with the triple kind of thoughts: negative (19 person), positive (17 person) and growing (19 person). There were negative correlations between adaptation of illness and personal growth. Conslusion. The familiarity of thoughts complements the picture of a seriously ill patient and facilitates the understanding of his behaviours.

Key words: psychological adaptation, personality development, thinking, patient.