Compounds of formula (I) and pharmaceutically acceptable salts thereof are disclosed: ##STR00001## wherein: A is optionally substituted phenyl, naphthyl, indolyl, quinolinyl, quinazolinyl, indazolyl, isoquinolinyl or benzofuranyl; X is carbon, Y is CH and ##STR00002## is a double bond; or X is CH, Y is CH.sub.2 or oxygen and ##STR00003## is a single bond; or X is nitrogen, Y is CH.sub.2 and ##STR00004## is a single bond; R 1 is halogen, cyano, or C.sub.1-6 alkoxy; a is 0,1, 2 or 3 ; b is 0 or 1 ; R 2 is hydrogen, C.sub.1-6 alkyl, C.sub.1-6 alkanoyl, fluoroC.sub.1-6 alkanoyl, C.sub.1-6 alkylsulfonyl, fluoroC.sub.1-6 alkylsulfonyl, carbamoyl, C.sub.1-6 alkylcarbamoyl or arylC.sub.1-6 alkyl; and R 3 , together with the nitrogen atom to which it is attached, forms an optionally substituted 5 to 7 membered heterocyclic group fused to the benzene ring. Methods of preparing the compounds and uses of the compounds in therapy, in particular for a CNS disorder such as depression or anxiety, are also disclosed.