The present invention provides a method of treatment of a subject suffering from a disease, such as schizophrenia, for which the administration of an NK-3 antagonist is indicated which comprises administering to that subject a therapeutically effective amount of a compound of formula I: ##STR00001## wherein, generally, Q is ##STR00002## R.sup.1 is benzyl, phenyl, thiophene or imidazolyl optionally substituted with C.sub.1-4alkyl or halogen, such as methyl, fluorine or bromine; R.sup.2 is hydrogen or C.sub.1-4alkyl such as methyl; R.sup.3 is phenyl; R.sup.4 is hydrogen; R.sup.5 is hydrogen or C.sub.1-6alkylcarbonyl such as methylcarbonyl; X is --SO.sub.2-- or --C(O)N(R.sup.2)SO.sub.2-- where R.sup.2 is preferably hydrogen; Y is a bond, CH.sub.2 or Z.sup.1 where Z.sup.1 is --N(R.sup.f)-- in which R.sup.f is C.sub.1-6alkylcarbonyl such as ethylcarbonyl; and R.sup.6 is phenyl, pyrazolyl, pyridyl, pyrimidinyl or benzimidazolonyl optionally substituted with one or two groups chosen from C.sub.1-6alkyl and benzyl, such as methyl, ethyl and benzyl; or a pharmaceutically acceptable salt thereof.