We present the case of a 27-year-old male patient who – without any apparent reason – jumped out of the window located at the 7th floor of the building, which resulted in severe injuries of internal organs. That shocking and inexplicable event became reason of many hospitalizations. He was hospitalized in the intensive care and rehabilitation units for months. He denied any suicidal ideation and was unable to give any reasonable justification for his jump. He was diagnosed with moderate depression and he was treated with antidepressants. Subsequently, psychotic symptoms appeared and he was hospitalized in psychiatric wards, where the diagnosis of schizophrenia was taken into account. He received antipsychotic treatment. At discharge, acute polymorphic disorder similar to schizophrenia was diagnosed. That act appears as “action against expectation” (actio praeter expectationem) – paragnomen – a concept announced by the Polish psychiatrist, Eugeniusz Brzezicki, in the 1950s. This case illustrates that an unfounded, unjustified by any meaningful reason and sudden event which led to several severe body injuries might be considered as a sign of the psychotic disorder development but does not have to necessarily result in the diagnosis of schizophrenia, as suggested by Eugeniusz Brzezicki, who was the author of the term ‘paragnomen’.