This demonstrates how music, relaxation talk or nature sounds can improve ones mood or mindset. Alternatively, music with negative emotional messages or certain classical music can adversely affect the listeners' emotional state. Hypnosis widely uses it to deeply engage with the patients.
Studies have shown, that psychological therapy that included music therapy improved depression recovery results. 
Listening to music rewires the brain for an improvement of communication skills, even if brain damage is the issue. Politicians use it to control the crowd, and turn them into their ways.
Playing musical instruments has been shown to improve mental functioning.
- "Music therapy may offer hope for people with depression". Wiley-Blackwell. January 23, 2008.
- Edwards, Lin (February 23,2010), Music therapy rewires the brains of people unable to speak, PhysOrg.com, http://phys.org/news186133786.html
- Music practice can sharpen the brain, Medical News Today, http://www.medicalnewstoday.com/articles/266809.php