Music therapy is a form of healing where music is used to enhance a persons overall health. It has been shown that music can have therapeutic affects on peoples physical and emotional health. Music therapy involves listening, dancing, singing and creating music and has been shown to help people better express their feelings. People respond to music in different ways, for instance the kind of music that you listen to is the same as the music your grandparents listen to. This is why all types of music can be used as therapy; it just depends on the person and what they like to listen to.
Here is a link to the Music Therapy Association website, which has a tone of information:music therapy