I've wondered many times in my life how childhood experiences play into mental health issues later in life? Are people from happy, positive homes and families more likely to escape mental health issues in adulthood or is there no particular correlation?

The older I get the more convinced I am that my own childhood experiences and family atmosphere have affected me more dramatically than I ever realized. I make a conscious effort every day not to dwell on things I wish had been different during my formative years but they're so obvious I can't totally get past them...I'm old enough and bright enough to know or believe the never ending negativity, criticism and somewhat overbearing/unrealistic demands I grew-up with have left an indelible mark on who I am today that I'll never overcome.

I'm curious. What chance do people who had negative childhoods have to reach adulthood unscathed by the past? Do those from happy, supportive, understanding, encouraging families usually grow up with those traits or do they have the same odds of having mental issues to deal with as adults? Are negative childhoods self-perpetuating? If an adult's mental issues stem from childhood and cannot be overcome, to what extent can they hope not to treat their own children similarly because that's all they've ever known?