There is provided a CRF receptor antagonist comprising a compound of the formula (I): A-W—Ar  (I) wherein, A is a group represented by the formula (A1) or (A2): (wherein, ring Aa is a 5- or 6-membered ring which may be further substituted; ring Ab is a 5- or 6-membered ring which may be further substituted; ring Ac is a 5- or 6-membered ring which may be substituted; R1 is optionally substituted alkyl, substituted amino, substituted hydroxy, etc.; X is carbonyl, —O—, —S—, etc.; Y1, Y2 and Q are independently optionally substituted carbon or nitrogen;  is a single or double bond); W is a bond, optionally substituted methylene, optionally substituted imino, —O—, —S—, etc.; Ar is optionally substituted aryl or optionally substituted heteroaryl; or a salt thereof or a prodrug thereof.