A compound selected from those of formula (I): wherein: R.sub.1, R.sub.2, R.sub.3 and R.sub.4, which may be the same or different, each represent an atom or group selected from hydrogen, halogen, alkyl, alkoxy, phenyl and cyano, X represents a bond, an oxygen atom or a group selected from --(CH.sub.2).sub.m--, --OCH.sub.2-- and --NR.sub.5--, wherein m represents 1 or 2, and R.sub.5 is as defined in the description, Y represents an oxygen atom or a group selected from NR.sub.7 and CHR.sub.8, wherein R.sub.7 and R.sub.8 are as defined in the description, Z represents a nitrogen atom or a CH group, n represents 1 or 2, Ak represents an alkylene chain, Ar represents an aryl or heteroaryl group, its optical isomers, and addition salts thereof with a pharmaceutically acceptable acid. Medical products containing the same which are useful in the treatment of conditions requiring a serotonin reuptake inhibitor and/or NK.sub.1 antagonist.