The present invention provides a novel compound and antidepressant composition that can be effectively used for improving depressed mood and depressed state, particularly for depressed mood and depressed state in menopausal women. The compound of the present invention is represented by the following formula (1): wherein R1 and R2 are identical or different and represent a hydrogen atom, a hydroxyl group or an acetyloxy group, and n is an integer of 2 to 7, or a pharmaceutically acceptable salt or ester thereof. This compound is used as an active ingredient in the antidepressant composition. Examples of the compound of the invention include (2E)-9,10-dihydroxy-2-decenoic acid, (2Z)-9,10-dihydroxy-2-decenoic acid, (2E)-9-hydroxy-2-decenoic acid, and (2E)-7-acetoxy-2-heptenoic acid.