Die Gnawa-Musiker in Südmarokko sind gleichzeitig auch Heiler. Wenn ein Patient kommt, beraten sie welche Farbe er braucht, und dann bekommt er "blaue" oder "gelbe" Musik vorgespielt.
Genaueres weiss ich leider auch nicht.
Edit:
Gerade im englischen Wikipedia gefunden:
Each of the seven families of mluk is populated by many "characters" identifiable by the music and by the footsteps of the dance. Each melk is accompanied by its specific colour, incense, rhythm and dance. These entities, treated like "presences" (called hadra, Arabic: ????) that the consciousness meets in ecstatic space and time, are related to mental complexes, human characters, and behaviors. The aim of the ritual is to reintegrate and to balance the main powers of the human body, made by the same energy that supports the perceptible phenomena and divine creative activity.
