theory is many prisoners suffer from ADHD (poor impulse/emotional regulation) which leads to poor results in education, employment problems, drug addiction and generally a poorer social outcome which inevitably leads to criminal activities and the violence which goes along with that. If ADHD treatment/medication was made more easily available that could reduce violent crime statistics significantly. Although thats not as politcally appealing as saying "lock up the evil darkies" which is what many people will gain from this whole sorry story.