1-(Benzofuran-2-yl)-2-propylaminopentane or a pharmacologically acceptable acid addition salt thereof is already known to exhibit an excellent activity/effect as an anti-depression drug, a psychotropic drug, an anti-Parkinson's disease drug and an anti-Alzheimer's disease drug. However, it is truly unknown that the compound is effective for the prevention or treatment of attention-deficit/hyperactivity disorder (ADHD). The present invention newly finds that the 1-(benzofuran-2-yl)-2-propylaminopentane or a pharmacologically acceptable acid addition salt thereof is effective for the prevention or treatment of ADHD. As a result, the present invention has been accomplished.
