(This turned out long, just to warn you ahead of time) I have an awesome family, we're all very close. Parents, a few older sisters and a younger brother. My parents are both very hard working and have always made sure us kids had the best they could provide. My sisters all have husbands, kids, jobs, just normal productive lives. My brother is in his last year of high school, and has had some issues but nothing major.
I managed to end up a heroin addict at 14. I can't really quantify everything that lead to it, it was a mix of bad decisions and a bad situation.
Cliff notes version. I was a very good student, all the top classes, set for a great future. But I was also a gay kid with an "alternative"/"gothic" fashion sense that did a great job of alienating class mates. I was also one of those kids that was too intelligent to mesh with kids my own age, but not really as mature as I thought I was or enough to deal with the situations I put myself in.
I started hanging around with an older crowd, lying about my age, having sex, doing drugs, the whole 9. I had been bullied at school for a long time but just kinda got on with it, but when I got a taste of having friends and fun I couldn't bring myself to deal with it anymore.
I stopped attending school properly, found ways to get my attendance mark without actually going to lessons, etc. This culminated in the school refusing to let me sit my end of year exams. So I didn't even get to sit my GCSE's.
I ended up moving to another city to live with my boyfriend as soon as school ended. My secret heroin use bloomed now that I didn't have to hide it from anyone. I got fucking awesome at emotionally blackmailing my parents to send me money.
Eventually, just before my 18th birthday, my boyfriend ended up in prison. Lost, I ended up moving back in with my parents. I tried to continue using heroin (which meant travelling to another city to "pick up") until I got found out. My mother forced me to seek help, and I started a heroin replacement script and got clean. Didn't relapse once.
The entire thing shook my family bad, and though it was 7 years ago, my life still hasn't recovered from me messing up at such a pivotal moment of my life.
So basically, I'm the black sheep, the mess. My siblings are normal, productive members of society just like my parents while I've suffered with addiction, mental health issues, being gay, being just generally different. My family have never treated me differently for it, in fact it likely makes them more protective over me. But I suppose I'm proof that it doesn't matter if you have an awesome, supportive family and no poverty, you can still go very wrong if you let yourself.