According to the present invention, a formulation or composition containing the same, and a preparation method thereof, a novel cocrystal free of hygroscopicity can be obtained by adding an organic acid such as salicylic acid to an anhydrous aripiprazole crystal. In addition, an industrially useful grinding process is provided, which enables the convenience of preparation of the cocrystal and workers safety to be ensured and allows the preparation of the cocrystal to be performed without needing a special chemical system.
