The present invention provides an agent for the prophylaxis or treatment of substance abuse and dependence, which contains a compound of the formula (I) represented by (R)-2-{3-[1-(acenaphthen-1-yl)piperidin-4-yl]-2,3-dihydro-2-oxo-benzimidazol-1-yl}-N-methylacetamide, or a pharmaceutically acceptable salt thereof as an active ingredient.
