The article describes the case of a 40-year-old woman who attempted suicide and killed two of her own children and was examined by three teams of forensic psychiatrists and psychologists for the purpose of judiciary. This women was somatically healthy, did not use psychiatric or psychological help. The authors were the third team of experts and, after conducting double psychiatric and psychological examinations and analysis of documents from the case files, which include the course of forensic-psychiatric observation, recognized the symptoms of dependant personality disorders and acute stress reaction, which resulted in a complete loss of the ability to recognize the meaning of the act and to manage proceeding. The paper discusses the diagnostic process as well as the analysis of psychotic disorders in relation to specific clinical diagnoses in accordance with the current classification of mental illnesses and disorders. Attention was paid to the problem of differentiating individual disorders and the way of defining psychotic disorders. The existence of difficulties in drawing the line between psychotic and non-psychotic disorders in the context of forensic psychiatric evaluation is emphasized.