Abstract: A class of substituted 1,2,3,6-tetrahydropyridine derivatives are disclosed that are ligands for dopamine receptor subtypes within the body. These compounds are therefore useful in the treatment and/or prevention of disorders of the dopamine system, in particular schizophrenia or depression.

Abstract: A class of chemical compounds comprising a benzo [b] furan moiety and a substituted heterocyclic moiety, linked via the 3-position of the benzo [b] furan moiety by a methylene group, are antagonists of dopamine receptor subtypes within the brain, being extremely potent antagonists of the human dopamine D.sub.4 subtype over other dopamine receptor subtypes, and are accordingly of benefit in the treatment and/or prevention of psychotic disorders such as schizophrenia while manifesting fewer side-effects than those associated with classical neuroleptic drugs.

Abstract: The present invention accordingly provides the use of a compound of formula I, or a pharmaceutically acceptable salt thereof or a prodrug thereof: ##STR1## wherein R.sup.1 represents hydrogen or C.sub.1-6 alkyl;Z represents --CH.sub.2 -- or --CH.sub.2 CH.sub.2 --;R.sup.2 represents hydrogen, C.sub.1-6 alkyl, C.sub.1-6 alkoxy, aryl(C.sub.1-6)alkyl or halogen;R.sup.3, R.sup.4 and R.sup.5 independently represent hydrogen, hydrocarbon, a heterocyclic group, halogen, cyano, trifluoromethyl, nitro, --OR.sup.a, --SR.sup.a, --SOR.sup.a, --SO.sub.2 R.sup.a, --SO.sub.2 NR.sup.a R.sup.b, --NR.sub.a R.sup.b, --NR.sup.a COR.sup.b, --NR.sup.a CO.sub.2 R.sup.b, --COR.sup.a, --CO.sub.2 R.sup.a or --CONR.sup.a R.sup.b ; andR.sup.a and R.sup.b independently represent hydrogen, hydrocarbon or a heterocyclic group;for the manufacture of a medicament for the treatment and/or prevention of psychotic disorders such as schizophrenia.