A use of an inhalable powder formulation for preventing or treating an NMDA receptor hypofunction-related disease, a method for preventing or treating an NMDA receptor hypofunction-related disease in a subject, which comprises administering a therapeutically effective amount of an inhalable powder formulation comprising growth hormone (GH) to the subject in need thereof, and an inhalable powder formulation for preventing or treating an NMDA receptor hypofunction-related disease comprising GH as an active ingredient are provided.