Aim. The main aim of the study was to present the case of a patient with neurological, depressive and psychotic symptoms, most probably connected with progressing dementia with Lewy bodies (DLB). Method. The systematic symptom analysis based on the clinical examination and medical documentation. Results. During the first hospitalisation, the presented patient was diagnosed with acute and transient psychotic disorders (F23). After being discharged from the ward, the patient experienced recurrence of previous symptoms with a short period of time. The two following diagnoses after hospital treatment were established as a depressive episode with psychotic symptoms. During the fourth hospitalisation, the patient was diagnosed with organic delusional (schizophrenia-like) disorder (F06.2). After six years, thorough analysis of clinical history as well as the course of existing disorder made it possible to diagnose the patient as having dementia with Lewy bodies-DLB (F02.8). Since that time, the patient has been taking rivastigmine, which has turned out to be a successful treatment. It has been 6 months since the patient left the hospital and still remains in remission. Social functioning of the woman is similar to the period before the first episode. Conclusions. The presented case demonstrates, that DLB symptomatology is a difficult problem in everyday psychiatric practice. A differential diagnosis of psychopathological and neurological symptoms covers many disorders, which together, with the clinical picture variation may delay effective treatment.