This study aims to validate the Lithuanian version of the Brief Negative Symptoms Scale, Calgary Depression Scale for Schizophrenia, and Schizophrenia Cognition Rating Scale in a Lithuanian sample. This will be done by comparing results obtained from the Brief Negative Symptoms Scale, Calgary Depression Scale for Schizophrenia, and Schizophrenia Cognition Rating Scale with results obtained from the Positive and Negative Symptoms Scale, the Montgomery Asberg Depression Rating Scale, and the Montreal Cognitive Assessment test.