Hello SongSungBlue... Different hospitals have different sorts of programs, but one would hope that going inpatient they would first, evaluate your symptoms and come up with a treatment plan, second, determine if and what medications might help you. As an inpatient they can monitor you closely for side effects while starting or stopping a medication or changing dosages, and three, maybe most important, fill your day with structure which can be very helpful for depression, and that structure would include some private and a lot of group therapy that includes education about mental illness and classes on coping skills giving you a chance to both learn and put them into practice.

As Little Cat said sometimes for some people it is a relief to go in, leave the life stressors outside, and just focus on your own health for a period of time.