There are some classical composers said to have been bipolar, though I think syphilis was a more likely diagnosis.  However, a comparison of the music of those supposedly bipolar with those not should show if there is any relation between psychosis and musical content.

These resources on music therapy for mental health may interest you:

https://books.google.com/books/about/Music_Therapy_Handbook.html?id=PVo8BAAAQBAJ

http://www.musictherapy.org/assets/1/7/MT_Mental_Health_2006.pdf

http://www.bamt.org/british-association-for-music-therapy-resources/bamt-information-leaflets.html

Dear Kayleigh Owens,

Bipolar disorder, also known as manic-depressive psychosis, is a mental illness characterized by atypical mood changes, energy swings and the ability to function. Unlike normal mood changes, with their ups and downs, which are inherent in everyone, the symptoms of bipolar disorder can lead to very serious consequences. They are able to destroy personal relationships, affect the quality of work or school performance, and even lead to suicide. Fortunately for us, bipolar disorder still gives in to treatment, and patients with this disease are able to lead a full and productive life.

Specialists at Cambridge University argue that rap music can be a real salvation for diagnoses such as schizophrenia, bipolar disorder, dependence, depression.

Thus, under the influence of rap patients who are not easy to tell about their condition, feel more motivated to communicate, helping to identify their problems. There are reasons to believe that people with mental disorders are comforted by rap, helps to put in order thoughts and feelings, makes more contact, the researchers concluded.

Regards, Shafagat

Dear Owens,

The following articles can be helpful for you

http://www.sciencedirect.com/science/article/pii/S0272735809000026

https://academic.oup.com/jmt/article/46/2/90/913237/The-Effect-of-Group-Music-Therapy-on-Quality-of

http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD004025.pub3/full

Let's ask dr Strzelecki.

https://www.researchgate.net/profile/Wojciech_Strzelecki