Ethan Couch was drunk and high when he drove his truck at 70 mph into a group of people, killing four. It was not his fault, though, he was suffering the dread disease “affluenza.” Warning: This episode will piss you off.
Sources:
https://www.psychologytoday.com/us/blog/our-gender-ourselves/201601/is-affluenza-real
http://thescienceexplorer.com/brain-and-body/affluenza-teen-s-psychological-condition-even-real