This is an interesting area which should be explored. Check out the graph above published by the Equality Trust, UK.
According to the Equality Trust:
The link between inequality and homicide rates has been shown in as many as 40 studies, and the differences are large: there are five-fold differences in murder rates between different countries related to inequality. The most important reason why violence is more common in more unequal societies is that it is often triggered by people feeling looked down, disrespected and loss of face.
We have also found that inequality is related to the Global Peace Index and to children’s experiences of violence.
The ground-breaking book The Spirit Level by Kate Pickett and Richard Wilkinson points to greater social problems with rising inequality. It shows that “for each of eleven different health and social problems: physical health, mental health, drug abuse, education, imprisonment, obesity, social mobility, trust and community life, violence, teenage pregnancies, and child well-being, outcomes are significantly worse in more unequal rich countries.”
The Equality Trust points to other research (C-C Hsieh ; M D Pugh, 1993) which shows that “poverty and income inequality are each associated with violent crime. The analysis, however, shows considerable variation in the estimated size of the relationships and suggests that homicide and assault may be more closely associated with poverty or income inequality than are rape and robbery.”
The Equality Trust observes: “Rates of violence are higher in more unequal societies. This finding holds up in many different contexts, when looked at via different methodologies and after controlling for other determinants of crime such as low income, unemployment, and teen birth rates.”
Inequality in many countries is often the result of neoliberal economic policies over many years.
Of course, there may be other factors contributing to violence, including the socio-economic environment.
My own view is that perhaps in a materialistic, capitalistic environment, people end up being seen as consumers or commodities or cogs in the assembly line. In the process, they end up losing touch with what it means to be compassionate human beings or being dehumanised to the structural “violence’ that has created misery in many societies.
Leaders must also take a strong and consistent position against the use of violence or mob rule, no matter where it occurs.