Also, and this crosses over to the parenting, online dating and the power of divorce threads: some people say that your inclination for mental illnesses is to a great degree biological and that we ought to stop blaming our parents for our difficulties.
This advice is counterproductive in the event that your depression is compounded with, perhaps even triggered by, abnormal parenting. Talking about my own childhood here. Actually, all of the following is based on my and my sister's lives so far, as well as what I've read on abnormal psychology (which is dabbling in an unfamiliar discipline, but I won't be making any outlandish conclusions, but am ofc happy to be corrected).
The findings that concern the majority of families where parenting is sub-optimal but the parents are normal can be used by some abnormal parents to avoid responsibility and further beat their traumatised children. We know that if the parents are fairly normal people, there will be all kinds of weaknesses and failures in their parenting, b/c people aren't perfect. I understand that research shows that most of the time, depression has a hereditary, biological component, and parenting is not a major contributing factor. However, this finding obfuscates those cases where the parenting really is actively harmful to the children, not just suboptimal.
Even as young kids, we both hoped to live with other families. Because it sucks ass to be beaten by your mom b/c her subordinate said something stupid during the work day. It sucks ass that your dad isn't interested enough in what happens at home when he's not there the times he does come home. I think I was 9 when I tabulated the yearly waking hours I spent with my biological mom (dad wasn't even there for 100-120 days on a given year, but he made mad bank as a CEO and major stockholder so I guess it was worth it) and was happy to find I spent as much time with the daycare professionals after school, who were just, you know, normal people. Unlike your parents, to who you're alternatively a bother, the heir, or an embarrassment, a disappointment, the thing holding them back from doing stuff that really matters, the person who has to take responsibility for the violence that you made them commit.
Why weren't the child protection services involved? Well, that would require that someone files a report. And we were scared to death of telling anyone anything, because mom had made sure we 'knew' how well connected she was and how no-one would believe us. Also, I was once careless and let it slip at a friend's house how scared I was for being late to home. Got well beaten and threatened about doing that again. Also, small town, affluent, well-connected parents, kids don't abuse substances and 'behave themselves'...
When my dad fell in love with another woman and left us, my mom's personality (disorder) got worse. I had forgotten an incident my sister told me about last week. It was a weekend and I was spending it with my friend (who has single-handedly saved my life a couple of times) and my sister calls me and she's crying and we go to our house and she's been beaten - we're 18 and 15 at this point - I take her to the next town, where dad now lives so that she's safe. Dad never even phoned or anything, but that one time I made him take my sister in. Shit. I get fucking emotional just writing this.
Of course, since the courts assigned custody of my sister to my mom, and my emotionally and socially retard of a father had tried to make my sister accept his new love as her new mom by taking my sister skiing for a week and 'by accident' have that lady and her son there as well... Right this was before the divorce. So my sister, who is pretty fragile from having been raised by a histrionic or narcissistic mom (my ex, the psychiatrist, declines to diagnose, but to quote her it's 'not a matter of if, but which diagnoses') was told about the divorce via letting her know that this woman here is gonna be your new mom. Fucking well played dad. My sister doesn't want anything to do with dad's new wife to this day, and I can't blame her. It would do her good, buut it's gonna be a long stretch of therapy before we get there.
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What I'm trying to say here is that sometimes, even if our life choices compound our depression, it is NOT our fault. If you've been beaten physically and verbally and made to feel worthless your entire childhood, it is exceedingly difficult to just up and say:'Okay, I'm 18 now, going to live on my own and fuck you both.' In fact, there's a small-ish minority of people that have been labelled 'resilients' (I think) who have the capacity for that. Not normal, it's almost a superpower.
Sometimes, you being fucked up is NOT your fault. YOU are still the ONLY ONE who can get you un-fucked, and doing that for yourself is your responsibility. But you being fucked right now is very possibly not your own fault.