Fused heterocyclic compounds

A method for treating obesity, drug addiction, or attention-deficit/hyperactivity disorder in a mammal, which comprises administering an effective amount of a compound represented by the formula (I) to the mammal:

• wherein
• ring A represents an optionally substituted 6-membered ring,
• any one or two of from Z1 to Z4 represent —N═, and the others represent —CH═;
• the nitrogen atom of —N═ for Z1 to Z4 may be oxidized;
• Y represents an oxygen atom, a sulfur atom, an optionally substituted methylene group or —NRc—;
• Rc represents a hydrogen atom, or a substituent;
• and
• R represents
• (1) a group represented by the formula:
• wherein
• R1 represents a phenyl group or 5- to 10-membered heterocyclic group, each of which is optionally substituted;
• L represents a sulfur atom, an oxygen atom, an optionally substituted methylene group, —CO—, —NRa—, —CH2O—, —OCH2—, —NRaCOO—, —OCONRa—, —NRaCONRb—, —NRaCOCH2—, —CH2CONRa—, —NRaCO—, —CONRa—,
• Ra and Rb are the same or different and each represents a hydrogen atom, or an optionally substituted C1-6 alkyl group, or
• L and R1 in combination optionally form an optionally substituted bi- or tri-cyclic fused heterocyclic group;
• and
• ring B1 represents a benzene ring, a pyridine ring, a pyrimidine ring, a pyrazine ring or a pyridazine ring, each of which is optionally substituted;
• or
• (2) a group represented by the formula:
• wherein
• R2 represents a phenyl group or 5- to 10-membered heterocyclic group, each of which is optionally substituted;
• and
• the partial structure of the formula:
• is
• wherein
• Rx1 and Rx2 are the same or different and each is a hydrogen atom or an optionally substituted C1-6 alkyl group,
• Rx3 and Rx5 are each a hydrogen atom or an optionally substituted C1-6 alkyl group, and
• the ring-constituting atom(s) of ring B2 and ring D optionally further have substituent(s),
• or a salt thereof.