Therapeutic agent for overactive bladder involved in aging

A process for screening a substance for suppressing overactive bladder involved in aging, comprising:

• administering a compound having a cholinesterase inhibitory activity, a pharmacologically acceptable salt or a solvate thereof to a non-human mammal;
• and detecting or determining a change in at least one selected from the group consisting of a bladder capacity, a bladder contraction pressure and an amount of retained urine, in the presence and absence of the compound, the pharmacologically acceptable salt or the solvate thereof.