The invention provides compounds of formula (I): wherein A and B represent the groups --(CH.sub.2).sub.m--and --(CH.sub.2).sub.n-respectively; R.sup.1 represents hydrogen or C.sub.1-6alkyl; R.sup.2 represents hydrogen, halogen, hydroxy, cyano, nitro, hydroxyC.sub.1-6alkyl, trifluoromethyl, trifluoromethoxy, C.sub.1-6alkyl, C.sub.1-6alkoxy, C.sub.1-6fluoroalkoxy, --(CH.sub.2).sub.pC.sub.3-6cycloalkyl, --(CH.sub.2).sub.pOC.sub.3-6cycloalkyl, --COC.sub.1-6alkyl, --SO.sub.2C.sub.1-6alkyl, --SOC.sub.1-6alkyl, --S--C.sub.1-6alkyl, --CO.sub.2C.sub.1-6alkyl, --CO.sub.2NR.sup.7R.sup.8, --SO.sub.2NR.sup.7R.sup.8, --(CH.sub.2).sub.pNR.sup.7R.sup.8--(CH.sub.2).sub.pNR.sup.7COR.sup.8, optionally substituted aryl, optionally substituted heteroaryl or optionally substituted heterocyclyl; R.sup.3 represents hydrogen or C.sub.1-6alkyl; R.sup.4 represents optionally substituted aryl or optionally substituted heteroaryl; R.sup.5 and R.sup.6each independently represent hydrogen, halogen, hydroxy, cyano, nitro, hydroxyC.sub.1-6alkyl, trifluoromethyl, trifluoromethoxy, C.sub.1-6alkyl, C.sub.1-6alkoxy, --(CH.sub.2).sub.pC.sub.3-6cycloalkyl, --(CH.sub.2).sub.pOC.sub.3-6cycloalkyl, --COC.sub.1-6alkyl, --SO.sub.2C.sub.1-6alkyl, --SOC.sub.1-6alkyl, --S--C.sub.1-6alkyl, --CO.sub.2C.sub.1-6alkyl, --CO.sub.2NR.sup.7R.sup.8, --SO.sub.2NR.sup.7R.sup.8, --(CH.sub.2).sub.pNR.sup.7R.sup.8, --(CH.sub.2).sub.pNR.sup.7COR.sup.8, optionally substituted aryl, optionally substituted heteroaryl or optionally substituted heterocyclyl; R.sup.7 and R.sup.8 each independently represent hydrogen, C.sub.1-6alkyl or, together with the nitrogen or other atoms to which they are attached, form an azacycloalkyl ring or an oxo-substituted azacycloalkyl ring; m and n independently represent an integer selected from 1 and 2; p independently represents an integer selected from 0, 1, 2 and 3; and either: Z represents --CR.sup.9R.sup.10X-- or --XCR.sup.9R.sup.10-- and X represents oxygen, sulfur, --SO-- or --SO.sub.2, or Z represents --CONR.sup.11-- or --NR.sup.9CO-- and X represents --CH.sub.2--, oxygen, sulfur, --SO-- or --SO.sub.2; R.sup.9 and R.sup.10 each independently represent hydrogen, C.sub.1-6alkyl or fluoro; R.sup.11 represents hydrogen or C.sub.1-6alkyl; or a pharmaceutically acceptable salt or solvate thereof. The compounds of the invention are useful in therapy, in particular as antipsychotic agents.