There are definitely some individuals in the hip hop industry who choose to glorify violence and hardship. They may do it because they are depressed and angry, insecure, or just because they are greedy and eager to go commercial. On the other hand, plenty of artists speak of the joy they experience(d) in an otherwise harsh environment. I’ve noticed this tendency among Southern rappers, whose lyrics and videos often include references to family, friends, food, music, and having a good time, despite growing up in poverty and “high crime areas”. There are also a few socially conscious lyricists out there who focus almost entirely on positive change in their community. Tupac had the unique ability to successfully express himself in each of these ways, depending on what he was feeling at that time.

I forget how long ago it's been but w/in the last few years... Essence Magazine put out an article regarding how many AA young men start to develop schizophrenia that can lead to their propensity to violence and crime.

Apparently, when hip-hop is used as an appropiate outlet, then these same young men find some level of self-care, treatment and soothing. However, they are still going untreated.

That's what I can remember off the top of my head.

But, the rappers are not the only AA men that have psychiatric disorders. I think the atheletes do too...

An overview of related studies:

African American Mental Health: Persisting Questions and Paradoxal Findings (*pdf)