https://www.bloomberg.com/news/articles/2011-07-06/zynga-s-q...
There were many articles covering this topic during the Zynga peak years, about folks developing gambling-type addictions to freemium games and spending money they don’t have.
EDIT: here’s another article exploring these connections... https://www.theverge.com/2015/5/6/8544303/casino-slot-machin...
And sadly even as far as violence is concerned - there was a horrific story a few years back about a woman who murdered her infant in anger when the child interrupted her FarmVille game.