Provided is a new serotonin-reuptake inhibitor that exhibits affinity for serotonin-1A receptors. Said serotonin-reuptake inhibitor is a compound represented by formula (1) or a pharmacologically acceptable salt thereof. In the formula, R1 represents a hydrogen atom, a 2-hydroxyethyl group, or a 2-methoxyethyl group. R2 represents one of the following bonded to a methylene group which is bonded to a piperidine ring: a chlorine atom bonded in a p-position; a bromine atom bonded in a p-position; a methyl group bonded in a p-position; a chlorine atom bonded in an m-position; or a bromine atom bonded in an m-position. Either Y1 represents a hydrogen atom and Y2 represents a hydrogen atom or a hydroxyl group, or Y1 and Y2 together represent an oxo group. Z represents a group represented by one of the following formulas: formula (3-1-1), formula (3-1-2), formula (3-2-1), formula (3-2-2), formula (3-3-1), formula (3-3-2), formula (3-4-1), or formula (3-4-2). However, if R1 represents a 2-hydroxyethyl group or a 2-methoxyethyl group and Y1 and Y2 both simultaneously represent hydrogen atoms, then Z represents a group represented by one of the following formulas: formula (3-1-2), formula (3-2-1), formula (3-2-2), formula (3-3-1), formula (3-3-2), formula (3-4-1), or formula (3-4-2).