The invention relates to a method for predicting a treatment response to a V1B receptor antagonist in a patient with depressive symptoms and/or anxiety symptoms, wherein the copeptin concentration in a blood sample of said patient is determined and/or the AVP concentration in a sample of cerebrospinal fluid of said patient is determined and wherein an elevated copeptin and/or an elevated AVP concentration compared to copeptin and/or AVP concentrations in healthy individuals is indicative for a patient responding to a treatment with a V1B receptor antagonist.