Neglect. Their parents work all the time so they hire nannies and the sort to take care of them so they can spend the day bringing in the money. Then they develop drug addictions to prescription meds and "rich" drugs like cocaine. I mean there was also that Lifetime story of some woman who lived in foster homes her whole life, was homeless at one point, and got into Harvard. Unfortunately people will read this and go "that's what's wrong with me/my kids!" and use it as a cop-out.