Multiple Personality Disorder is treated by a hypnotic suggestion, "talk-therapy"and regular counseling.
But this treatment does not go away in a few days, it's a long-term treatment! MPD can be cured. It is highly responsive to individual "talk therapy". There are also other medications and hypnotherapies, that help.
Therapy is long-term and can also be very painful, because you have to remember the traumatic experiences.
MPD can be cured once all of the 'personalities are out in the open, and the individual with MPD remembers everything clearly, and can become 'one' again.
A lot of people confuse Multiple Personality Disorder with schizophrenia, because schizophrenia means "split personality" so people think Multiple Personality Disorder is related to "split-personalities"(schizophrenia) but they are NOT related! Also both are confused of the same thing because both diseases hear voices in the head.