Abstract: Compounds of formula (I) and pharmaceutically acceptable salts thereof are disclosed: wherein: A is optionally substituted phenyl, naphthyl, indolyl, quinolinyl, quinazolinyl, indazolyl, isoquinolinyl or benzofuranyl; X is carbon, Y is CH and is a double bond; or X is CH, Y is CH2 or oxygen and is a single bond; or X is nitrogen, Y is CH2 and is a single bond; R 1 is halogen, cyano, or C1-6 alkoxy; a is 0,1, 2 or 3 ; b is 0 or 1 ; R 2 is hydrogen, C1-6 alkyl, C1-6 alkanoyl, fluoroC1-6 alkanoyl, C1-6 alkylsulfonyl, fluoroC1-6 alkylsulfonyl, carbamoyl, C1-6 alkylcarbamoyl or arylC1-6 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.