"What came first, the music or the misery?" -High Fidelity
If a person's environment is a determining factor in the development of personality, then music listened to, especially during adolescence, tends to become a personal brainwashing device. Depending on the genre and subject matter--whether it be religion, hate, happiness, angst, love, or jealousy--a single song can be a catalyst of influence, sending abstractions of emotion to surround a person's entity. This ultimately affects the individual's mental state, which is then carried on into adulthood. But, there is the factor of personal selection. You pick the music to listen to...so choose wisely.