This invention relates to the use of (4-benzylpiperazin-1-yl)-[2-(3-methylbutylamino)pyridin-3-yl]methanone (NSI-189) or a pharmaceutically acceptable salt thereof in the treatment of a psychiatric condition in which depressive symptoms are prominent, including major depressive disorder (MIDD), bipolar disorder, post-traumatic stress disorder, substance use disorder, and depression-related aspects of schizophrenia (e.g. negative symptoms) in select patients who exhibit impaired learning and/or memory. The invention also relates to the use of NSI-189 or a pharmaceutically acceptable salt thereof in the treatment of a psychiatric condition in which depressive symptoms are prominent, including major depressive disorder (MDD), in select patients who exhibit impaired learning and/or memory or certain EEG characteristics.